HDFC Bank Payzapp — Not posting the cash back as promised

Website:

v1.hdfcbank.com/htdocs/common/PayZapp/index.html

I made the payment on Aug-25-2020.Suppose to be cash back need to be posted within 10 working days form Transaction date.It was not done until now.
This issue is not happening for first tie every time I need to ask and send request for the cash back.
It was happening regularly and there is no communication for same.