Bajaj Finance — Did not get cashback

Bajaj Finance executive suggested paying an additional 1250 INR to get cashback of 2500 while buying washing machine at Maharashtra Electronics, Tilak Road, Pune and said I will get cashback after my 2 EMI's are deducted. But, I didn't get cashback for around one year. Then, I decided to follow up with Bajaj Finance to get the vouchers, finally, they provided them to me after multiple follow-ups. But, I could not redeem them due to a medical emergency.
But, now when I am reaching out to them they are lying and not providing coupons. This is the reply from them.

"As discussed on call xxxxxx6860 and with reference to your email, we wish to inform you that we have again check with concern department and we have received conformation that they had not run any coupon code to redeem the cashback. Hence cashback is not eligible.

We sincerely apologize for the inconvenience that has been caused and appreciate your understanding and patience."