Bajaj Finserv — Regarding store credit

I purchased laptop on 2021 during Diwali 10k offer. As I was mentioned I have 8000 cashback offer after successful clearance of 3 emis . I cleared all emis .The redemption period is up to 31september 2022. When I contacted customer support they were telling that it was expired on 31st July 2022. According to company rules redemption period is up to sep31st. Loan reference number 400CDDHL650269.please try to solve my issue. I went to redeem my store credit but the Bajaj employees refused to redeem as the code Is expired.