Zomato — refund not given by zomato

Address:

41-20/5-58, Kalpana Prints Road, Krishna, Andhra Pradesh, 520013

I placed a order in zomato on 16th september 2019 and paid rs.71/- through my debit card also.
But i didn't get my order, and after more than 1hour long discussion they simply cancelled my order..
And they clearly said they will refund 71/- to my bank account and additionally 71 zomato credits to my zomato account..
They added 71 credits in zomato account
& they initiated refund of rs.35.50/- to my bank account.. They are simply telling you this is the only refund you get..
Why should i pay full amount of order and now they are paying half amount only?

Attached screenshot of chat conversation with zomato executive's promise.