HDFC Bank — regarding fastag

I have applied for Fastag through HDFC Bank online portal on dated 29/11/2019. There is two transaction of Rs.500/- each. First one was showing error after money had been cut from my account. Second try is successful and another Rs.500/- had been cut from my account. Since then i had tried many times to contact the Customer care of HDFC Bank Fastag but the phone is goes unanswered or many times not connected. I had contacted to the Relationship manager but she is helpless in this matter. Recently I got a reply through mail on dated 5/12/2019 but than there is no response or no communication through mail whether the fastag has been delivered or not. Tried many forms to contact HDFC Bank but with no response. Very irritating...