HDFC Bank Bank Fastag — faulty tag, not operational since day 1. no response from hdfc

Address: 560104

I was issued a Fastag for my vehicle on 9th August 2019, however the tag is defective and has not been accepted at any of the fastag toll booths across Karnataka. The Toll gate machines have not been able to scan and everytime I have ended up paying in cash.

I requested immediate replacement of my fastag. Spoke to the customer care and even sent an email to fastag.[protected]@insolutionsglobal.com but surprisingly there is absolutely no response from them.
Have sent multiple reminders and follow-up emails, but no response whatsoever.