HDFC Bank — no information about my fastag application

Address:

Vishwakarma Colony, New Delhi, Delhi, 110044

I paid for HDFC Fastag and an application number was generated for which I received an email as well. I have been trying to call the customer service number mentioned for HDFC Fastag i.e.[protected] however i can only hear 1 thing "the subscriber is busy at the moment. Please call after sometime". I have made 30 attempts over the last 4 days to somehow get in touch but to no avail. I have not even been contacted by any representative as promised in the email but that too has not taken place. So all in all, money deducted from my HDFC account but i dont know if ever I will get the Fastag or when will I get it. There is no email address as well to complain. My application number is HFR441401.