Jurisdiction of filing

Dear Sir I am a trader of machines based in West Bengal (mineral processing machines). One of my customer based out of Rajasthan has purchased a machine from us in Sept 2016. The machine was manufactured and supplied to me by my supplier, who is also based in West Bengal. The supplier had sent an inquiry of the machine and after lot of discussions over telephone / watsapp / sms the customer visited my supplier's premises and agreed to buy a product. We had given him a hard copy of the quotation for the machine and he gave us go ahead for the same. He had brought some sample of minerals with him which we checked at my supplier's factory on a prototype machine. After delivery of the machine, the customer mentioned over phone and sms about not getting desired result and one technician was sent to the customer's factory in Rajasthan for checking. To our surprise we noticed that customer is using a different grade of material against what was shown during customer's visit to my supplier's plant. He also asked us to change the machine at no additional cost to which we regretted. Now the customer is threatening us for legal action for Conspiracy, Fraud, Betrayal etc. in Rajasthan court. We in our quotation had mentioned that customer to test the machine prior to shipment of the consignment, but he did not come for testing. Also to be noted the following:- a) No sales agreement was signed. b) No Purchase Order was issued. c) No formal complaint was email to us. d) Only the quotation was handed over with the scope of the machine. Please advise your expert comments on this case.