[fix] Duplicate Customer Name Error
diff --git a/erpnext/selling/doctype/customer/customer.py b/erpnext/selling/doctype/customer/customer.py
index 21f6578..e219fdb 100644
--- a/erpnext/selling/doctype/customer/customer.py
+++ b/erpnext/selling/doctype/customer/customer.py
@@ -6,7 +6,7 @@
 from frappe.model.naming import make_autoname
 from frappe import _, msgprint, throw
 import frappe.defaults
-from frappe.utils import flt
+from frappe.utils import flt, cint, cstr
 from frappe.desk.reportview import build_match_conditions
 from erpnext.utilities.transaction_base import TransactionBase
 from erpnext.utilities.address_and_contact import load_address_and_contact
@@ -23,12 +23,21 @@
 	def autoname(self):
 		cust_master_name = frappe.defaults.get_global_default('cust_master_name')
 		if cust_master_name == 'Customer Name':
-			self.name = self.customer_name
+			self.name = self.get_cusotmer_name()
 		else:
 			if not self.naming_series:
 				frappe.throw(_("Series is mandatory"), frappe.MandatoryError)
 
 			self.name = make_autoname(self.naming_series+'.#####')
+			
+	def get_cusotmer_name(self):
+		if frappe.db.get_value("Customer", self.customer_name):
+			count = frappe.db.sql("""select ifnull(max(SUBSTRING_INDEX(name, ' ', -1)), 0) from tabCustomer
+				 where name like  '%{0} - %'""".format(self.customer_name), as_list=1)[0][0]
+			count = cint(count)+ 1
+			return "{0} - {1}".format(self.customer_name, cstr(count))
+		
+		return self.customer_name
 
 	def validate(self):
 		self.flags.is_new_doc = self.is_new()
@@ -225,4 +234,4 @@
 		credit_limit = frappe.db.get_value("Customer Group", customer_group, "credit_limit") or \
 			frappe.db.get_value("Company", company, "credit_limit")
 
-	return credit_limit
+	return credit_limit
\ No newline at end of file
diff --git a/erpnext/shopping_cart/cart.py b/erpnext/shopping_cart/cart.py
index 22f920f..aa6e5e3 100644
--- a/erpnext/shopping_cart/cart.py
+++ b/erpnext/shopping_cart/cart.py
@@ -303,7 +303,6 @@
 		contact.insert(ignore_permissions=True)
 
 		return customer
-
 def get_address_docs(doctype=None, txt=None, filters=None, limit_start=0, limit_page_length=20, party=None):
 	if not party:
 		party = get_customer()