Paytm — Not responding to mails related to cashback

Address:

Bangalore, Karnataka

Paytym runs an offer with groupon, On minimum purchase of 500 get 550 rs cashback Mine order worth rs 799 is already delivered and it been 2 weeks placing the order, Paytym is not refunding the cashback. got two replies saying sorry for the delay, we are working on the issue. and now they have stopped responding to my mails. Dropped voicemails on their tollfree no.