Apollo Hospital Hyderabad - Payment received but no service provided

I have booked virtual doctor consultation (Jubilee hills, Hyderabad) on *rd April using Apollo *** app. I made the payment through PayTM (using HDFC) for Rs ***. Amount got withdrawn from bank however there was no payment confirmation received not the appointment was booked. I reached out to customer care number and was told that they can't take complaints and I need to raise the concern through Apollo *** App or by sending mail. I have sent around *-* complaints over mail and apollo *** app. There is NO response, NO acknowledgement. I have contacted bank and confirmed that the payment is done and they can initiate refund once they get some information from merchant that it was not successful.
I am helpless here and not sure how I can get my refund for the service which I didn't receive.