HDFC Bank — fastag issued, but not yet delivered

Address:

Deoria, Uttar Pradesh, 263153

I applied for a fastag on hdfc fastag link
On 30th of november, 2019. I paid inr 500 for this application. On 6th dec i got a notification that my fastag has been issued. I did not receive any information on how the fastag has been sent, to which address, when can i expect to receive it. No courier details are provided. I tried reaching the cc number which is always busy. I also logged into the fastag portal and lodged a complaint but no response or resolution till now. Bank cc says they are not aware of fastag details and cannot help. How do i get this resolved? I need my fastag immediately as it is 12 december now and only 3 days are left.