got screwed on the Buy 2999 and above and get 1000 cash back offer-- complete money not refund and taken from cashback

Hi I ordered two toys totally 3000rs, one toy costing 1699 was delivered fine the other one costing 1400 was damaged and had to be returned and money refunded… I pay for both item total 3099 and got refunded 1000 so actually i got the two items for 2099
but when i return the damaged items costing 1400 PAYTM returned back only 400 saying that the other amount was already given back as part of cash back… this is fraud…its not customer fault that item is recieved damaged in the process I have now payed for the full amount for the second toy costing 1699( no cash back considered here after the refund).. really pathetic…
I recommend not to buy two products in one order when selecting for cashback since you could get screwed like i did.
Always by one item in case it is faulty then you will recieve the balance vis refund for that item only and dont get screwed on cashback.