Authorised Blackberry Service Centre Denied to give bill for service

Location/place: Bhopal MP

Name of company/service: Sampark System

Name: Sampark System
Address: Ug-22 Kartar Arcade Main Raisen Road Near Captial Petrol Pump
City: Bhopal
STD Code: 0755
Phone Numbers: 4078556/9826010158
Service Type: GSM

I wanted to get my mobile repaired.My Blackberry 9300 had some problems with trackpad.The service centre incharge quoted estimated price to be 1350/- without bill.I said that i want a bill and in reply he denied of giving service.