HDFC Bank Bank Fastag — utterly unreliable service

Stay away from hdfc fastag. Today on 29 nov 2019, i have applied for fastag through fastag campaign on their bank portal. I made payment rs.500 through debit card. Till the payment transaction, portal was working fine. The moment after i entered otp, that's it. Amount deducted from the bank and portal returned error page. When i check with bank cc, they confirmed amount was debited. And i have been told that to call hdfc fastag customer care number[protected].
This never be reachable. And surprisingly no email to contact. My other car has icici fas tag since 2017, i never had this kind of issue with them. Their cc is much better than these *.