diff --git a/erpnext/healthcare/doctype/patient/patient.json b/erpnext/healthcare/doctype/patient/patient.json
index cf09292..e69b410 100644
--- a/erpnext/healthcare/doctype/patient/patient.json
+++ b/erpnext/healthcare/doctype/patient/patient.json
@@ -157,8 +157,7 @@
    "fieldtype": "Link",
    "ignore_user_permissions": 1,
    "label": "Customer",
-   "options": "Customer",
-   "set_only_once": 1
+   "options": "Customer"
   },
   {
    "fieldname": "report_preference",
@@ -363,7 +362,7 @@
  "image_field": "image",
  "links": [],
  "max_attachments": 50,
- "modified": "2020-01-31 17:50:59.797789",
+ "modified": "2020-02-25 12:07:41.751539",
  "modified_by": "Administrator",
  "module": "Healthcare",
  "name": "Patient",
diff --git a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.json b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.json
index ea0075c..f9dc892 100644
--- a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.json
+++ b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.json
@@ -226,10 +226,9 @@
    "default": "0",
    "fieldname": "invoiced",
    "fieldtype": "Check",
-   "in_filter": 1,
+   "in_list_view": 1,
    "label": "Invoiced",
-   "read_only": 1,
-   "search_index": 1
+   "read_only": 1
   },
   {
    "fieldname": "company",
@@ -279,7 +278,7 @@
   }
  ],
  "links": [],
- "modified": "2020-02-24 21:29:28.374886",
+ "modified": "2020-02-25 11:29:26.988952",
  "modified_by": "Administrator",
  "module": "Healthcare",
  "name": "Patient Appointment",
diff --git a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.py b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.py
index 4ae079a..ecabbe3 100755
--- a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.py
+++ b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.py
@@ -19,6 +19,7 @@
 	def validate(self):
 		self.validate_overlaps()
 		self.set_appointment_datetime()
+		self.validate_customer_created()
 
 	def after_insert(self):
 		invoice_appointment(self)
@@ -58,11 +59,18 @@
 			overlapping_details += '<br>'
 			overlapping_details += _('{0} has appointment scheduled with {1} at {2} having {3} minute(s) duration.').format(
 				overlaps[0][1], overlaps[0][2], overlaps[0][3], overlaps[0][4])
-			frappe.throw(_(overlapping_details))
+			frappe.throw(overlapping_details, title=_('Appointments Overlapping'))
 
 	def set_appointment_datetime(self):
 		self.appointment_datetime = "%s %s" % (self.appointment_date, self.appointment_time or "00:00:00")
 
+	def validate_customer_created(self):
+		if frappe.db.get_single_value('Healthcare Settings', 'automate_appointment_invoicing'):
+			if not frappe.db.get_value('Patient', self.patient, 'customer'):
+				msg = _("Please create a Customer linked to the Patient")
+				msg +=  " <b><a href='#Form/Patient/'>{0}</a></b>".format(self.patient)
+				frappe.throw(msg, title=_('Customer Not Found'))
+
 	def update_prescription_details(self):
 		if self.procedure_prescription:
 			frappe.db.set_value('Procedure Prescription', self.procedure_prescription, 'appointment_booked', 1)
@@ -84,6 +92,7 @@
 				frappe.db.set_value('Fee Validity', fee_validity.name, 'visited', visited)
 				if fee_validity.ref_invoice:
 					frappe.db.set_value('Patient Appointment', self.name, 'invoiced', True)
+					frappe.db.set_value('Patient Appointment', self.name, 'ref_sales_invoice', fee_validity.ref_invoice)
 				frappe.msgprint(_('{0} has fee validity till {1}').format(self.patient, fee_validity.valid_till))
 
 
@@ -105,14 +114,15 @@
 		item = get_appointment_item(appointment_doc, item)
 
 		payment = sales_invoice.append('payments', {})
-		payments_line.mode_of_payment = appointment_doc.mode_of_payment
-		payments_line.amount = appointment_doc.paid_amount
+		payment.mode_of_payment = appointment_doc.mode_of_payment
+		payment.amount = appointment_doc.paid_amount
 
 		sales_invoice.set_missing_values(for_validate=True)
-
+		frappe.as_json('Sales Invoice')
 		sales_invoice.save(ignore_permissions=True)
 		sales_invoice.submit()
 		frappe.msgprint(_('Sales Invoice {0} created as paid'.format(sales_invoice.name)), alert=True)
+		frappe.db.set_value('Patient Appointment', appointment_doc.name, 'invoiced', True)
 		frappe.db.set_value('Patient Appointment', appointment_doc.name, 'ref_sales_invoice', sales_invoice.name)
 
 
@@ -223,12 +233,13 @@
 	if practitioner_doc.practitioner_schedules:
 		slot_details = get_available_slots(practitioner_doc.practitioner_schedules, date)
 	else:
-		frappe.throw(_('{0} does not have a Healthcare Practitioner Schedule. Add it in Healthcare Practitioner master'.format(practitioner)))
+		frappe.throw(_('{0} does not have a Healthcare Practitioner Schedule. Add it in Healthcare Practitioner master').format(
+			practitioner), title=_('Practitioner Schedule Not Found'))
 
 
 	if not slot_details:
 		# TODO: return available slots in nearby dates
-		frappe.throw(_('Healthcare Practitioner not available on {0}').format(weekday))
+		frappe.throw(_('Healthcare Practitioner not available on {0}').format(weekday), title=_('Not Available'))
 
 	return {'slot_details': slot_details}
 
@@ -243,7 +254,7 @@
 	if employee:
 		# check holiday
 		if is_holiday(employee, date):
-			frappe.throw(_('{0} is a company holiday'.format(date)))
+			frappe.throw(_('{0} is a holiday'.format(date)), title=_('Not Available'))
 
 		# check leave status
 		leave_record = frappe.db.sql("""select half_day from `tabLeave Application`
@@ -251,9 +262,9 @@
 			and docstatus = 1""", (employee, date), as_dict=True)
 		if leave_record:
 			if leave_record[0].half_day:
-				frappe.throw(_('{0} is on a Half day Leave on {1}').format(practitioner_doc.name, date))
+				frappe.throw(_('{0} is on a Half day Leave on {1}').format(practitioner_doc.name, date), title=_('Not Available'))
 			else:
-				frappe.throw(_('{0} is on Leave on {1}').format(practitioner_doc.name, date))
+				frappe.throw(_('{0} is on Leave on {1}').format(practitioner_doc.name, date), title=_('Not Available'))
 
 
 def get_available_slots(practitioner_schedules, date):
@@ -267,7 +278,7 @@
 			practitioner_schedule = frappe.get_doc('Practitioner Schedule', schedule_entry.schedule)
 		else:
 			frappe.throw(_('{0} does not have a Healthcare Practitioner Schedule. Add it in Healthcare Practitioner').format(
-				frappe.bold(practitioner)))
+				frappe.bold(practitioner)), title=_('Practitioner Schedule Not Found'))
 
 		if practitioner_schedule:
 			available_slots = []