HDFC Bank — I didn't get my fastag sticker even after a month

Address:

Bangalore

I have applied for fastag via hdfc online with refernce number HR[protected]. After applying, i got message stating that filled form pdf will send to your registered email, which i didn't receive yet.
After few days i got a message with my wallet id and customer id[protected]. So now i am able to login to site, but so far i didn't receive fastag sticker. I tried to call customer support - [protected] multiple times but nobody is picking the call. Then i tried to call pos number of bangalore [protected], but again the same, nobody picks the call. Even i didn't receive any call from any of the courier services.
I have 8 years of relationship with hdfc and never face such scenario. But for specific to fastag service this is happening. With this i am bit scared, how can i get help if i stuck in some toll plaza, as nobody is receiving the call.