If you have not looked at using HLR Lookup for Premium Billing then look again.
For customers on Wifi, service providers can use HLR to benefit their advertising and save costs.
Why use HLR for Premium Billing?
HLR can save money on acquisition costs by identifying if the service provider should send the opt in (PIN, OTP or Keyword).
Use look up to check network to see if traffic source is on the advertisers cpa.
Use look up to check if number entered is active and if user is valid.
Once the number is checked using HLR, you can:
Send PIN or keyword information when mobile number is correct.
Send PIN or keyword information when network is correct.
For Bulk routing:
Send PIN or keyword information on best possible bulk route.
You can periodically HLR users to make sure your subscribers are active.