HDFC Bank — Fastag issue

I have mailed HDFC for my fastag issue on their email, they are so irresponsible that they do not reply to my any mail, It has been happening from 16th October 2020 to till date 21st December 2020 and no response from their side. The fastag is not available to us and the amount is deducted from my fastag without going anywhere. I have my car without fastag, I submitted the complaint on the day this happen, I want to know why this happens, apart from that I want my fastag for myself. Through that I tried regularly email that they will see but they are no replying at all. You cas see at my snapshots. So if you're going to buy fastag from this I'll suggest you that don't go with them they are very irresponsible to their customers.