HDFC Bank — fastag not received

I had applied for fastag on 26/11/2019 thru following hdfc fastag portal.
https://getprepaidcard.hdfcbank.com/fastag/index.aspx

I have a HDFC bank salary account and paid the amount through my standard chartered credit card.
Payment of Rs. 500/- got debited to my credit card but didn't receive any response or communication from hdfc (No message /email)

Following are my details:
Name : Deepak Kumar Garg
Mobile no: [protected]
Email id: garg.[protected]@gmail.com
Vehicle no: KA01MH4434
Model: Honda City

I have tried calling the toll free no: [protected] more than 25 times over last 2 days but it is always coming busy.
I felt cheated and need an immediate response from hdfc fast tag team.
Please revert as soon as possible.