MTS / Sistema Shyam TeleServices [SSTL] — dongle old device support was not their and refund also they are not providing for recharge made

Address:

Bangalore, Karnataka, 560098

I did a recharge for Rs. 1599 and device was working for few days. Suddenly the light glowing stopped and no network connectivity. When the due date to renew, i did a recharge for Rs. 299, - so my Old balance won't be lost . Whereas when i took my device for servicing, they didn't even examined what is wrong in the device. Just asked the model and mentioned that they don't provide any support.
Very poor and worst service - customer care is really bad. Have to send several emails. At least whatever i did a recharge for 1599 INR 32 GB + 299 INR to carry forward the remaining data, they are not reimbursing / not responding to any of the emails which i send.'
Have sent several emails, no use at all. And they didn't even acknowledge, even after i mentioned that i am going to raise a consume complaint. Worst customer care as well.