HDFC Bank — fastag application

Trying to track fastag application no.: hr[protected]
Got an email stating that the application was approved and shall receive the fastag within 7 days. But already been more than 10 days, there is no way to track the application. Very tiresome customer service with no luck on customer care number as they never answer. Also no other way to connect to them for this issue. No email id for grievance of fastag.
Please help us resolve.