Hi, New here ENV Touch TEXTING issues & dropping calls

K im on my second ENV VX11000 with the same problem as the last. the first was a verizon and this one is through a different carrier.
basically my phone will hit dead mode out of nowhere all the functions are there but my texting goes away it will not send or receive text or phone calls, also the internet on it will go dead for 10-30 minutes at a time. The phone will still function as far as play music and display videos or pictures on my memory card. But the calling and texting thing is frustrating beyond measure. If I take the battery out and put it back in it makes no difference. The phone will reboot into the same problem. it seems like the phone does what it wants when it wants to. Is there some kind of fix that anybody knows of?

VZ Navigator will not work as well. As far as the messages go it says Send failed. Would you like to retry? >yes
            >no
If I click yes it will just do the same again
 
My GF has the same service provider and has no issues like this. we can be texting each other side by side and mine will fail to send.