Sony service center khammam - Mobile phone repair

As I purchased lava z** mobile in Big c khammam in july ****.
In may **** it got charging problem. The mobile has * years warrenty and also I have taken mobile guard insurence for this mobile in big c at the time of purchase.
I noticed this problem to bigc showroom. They advised to take the mobile to sony service center. I approached there. They refused to give service being i had * years warrenty. As it had a small scratch over the screen. They advised me to replace the screen at my own expenses of rs **** and after i have to reiemburse the amount through insurence company. I agreed and paid the amount in may ****.
After that they said insurence company rejected my claim. The sony service center persons didnot repair my mobile they postponed the delivery date and delayed for two months.
In august they gave me my mobile which was not working properly. I re return the mobile for repair. They resend the mobile without any repairs. Still now i have to maintain without a mobile phone.