Lifestyle Home Centre — cashback issue with vendor

Address:

Home centre seawoods mall seawoods Navi Mumbai, Mumbai City, Maharashtra

I had purchased a dinning table and some other stuff from home centre seawoods store on 6 january 2018, total bill amount was ₹.39900 and there was a 5% cashback offer by paying through hdfc bank debit card and i did so to avail the cashback offer. But cashback has yet not yet credited to my account.
Invoice no: [protected]
Customer id:[protected].
Reference number for transaction[protected]. As hdfc bank says the vendor has not issued the cashback.
Its been more than 18 months.