Tanishq — Voucher Fraud

Pine Labs has the worst customer service ever. On the 1st of August 2022 I generated my Pine Perks rewards into a Tanishq voucher and the showroom told me that they were not authorized to use the voucher and I had to pay them in cash. On calling Pine Perks customer care I was informed that the voucher would only work in Titan showroom. The voucher had close to Rs 10k.
When I tried to use the said voucher at the Titan showroom, I was informed that the voucher has no balance which was not informed to me by Pine Perks. Now, the customer care is arguing that the voucher has been used.
I have been continuously emailing them and calling them from 1st august. Only to hear from them that the voucher has been used, which has never been used. They are not ready to provide any solution. They have taken away my money and are harassing me uselessly. I have all the transaction details supporting my claims. I have made cash payment in Tanishq and not purchased anything from titan then how can they say that the voucher has been used?
After multiple calls and complaints they have only sent me the redeemer details and are not willing to take any further action against the redeemer