Multiple issues with Nokia Lumia 635

[hinata1394]

I recently switched to straight talk with a T Mobile no contract Nokia Lumia 635.
I have been unable to send picture messages, as many people are having trouble doing, and I also can't send group chats. Also, my phone keeps dropping service, (as in I'll have two bars of service in an area, an then for no reason it will have no bars, with the little no signal,) and I have also not been unable to connect to the internet if not on WiFi, even if I'm in a 4G area.
I have tons of friends who have straight talk an have none of these issues, but all their phones are straight talk phones, not T Mobile.
I'm wondering if it's my phone, or my settings, or my straight talk service. I really want to keep straight talk and my phone, does anyone have the same issues or possible solutions?

[ST-Kurt]

Hi hinata1394! Our sincerest apology for what had happened. This is Straight Talk Kurt. I will contact you directly with a private message to fix the issue. Thank you.