Nokia C5
Technical problem

We have purchased Nokia c5 phone in the month of may from that date we have taken our phone to nokia care service center 10 times but no use, our phone is still in problem. recently ten days before they have changed the mother board of my phone also. but still the problem is there. suddenly phone turns to white screen, and touch screen will not be operated, and not getting connection. (network no coverage). sometime it is getting very hot. my phone no is 9440630176.