HDFC Bank — Fastag not delivered

I have paid for fastag in the month of december 2019 app no: hfr847127 but not yet received the fastag to my address.. It's been almost more than 8 months and i have called customer service and asked for a refund and they said the refund amount will get credited within 3 days but i haven't received a single amount. And no reply for my emails.

Now, i need to get the refund and as well as compensation for making me to wait for long time in the toll gate.