How do I get someone to honor Warranty?

Have Envizen 10 Tablet thru HSN less than a yr ago. It is broken. Screen cracked when it slipped out of my hands and landed on car door threshold. It was properly in the protective case at the time. Unrelated and prior to this I having trouble w the E and G signs up at the info corner where the WiFi signal is displayed. I get 200mg/ month from T-mobile but also have WiFi and regardless if either one, I have connect issues no matter where I'm at. It also freezes a lot and in general I use all 200mg's just trying to get a signal wout an E or G or just trying to get on a site or fill out a form....etc. I imaginbe I need someone to verify this info and see if I qualify for warranty. I already spoke to a T-Mobile agent by pH and she had said, I do qualify and to go to T-Mobile but they had no idea what I was talking about there and never have seen the Tablet before. So where do I go? Call? Thank you ahead of time. Rose