We want to know which cell phone carrier someone who subscribes to our text messages is using. We're currently using an API from [url removed, login to view] but it gives many wrong answers. We're receptive to using a gateway or whatever it takes but our volume is hundreds and most seem way too pricey.
My company has written .NET 3.5 Visual Studio software that uses email technology to send automated text messages to subscribers who opt-in. It sorta works but it requires subscribers to pick their call phone carrier from our list. They don't pick the right one, which results in bounces and messages failing.
We need a fix and are willing to pay.