I am sorry you are having coverage issues. Is this happening everywhere? We need to check your coverage and we can also reset the connection.
What I would like to start with is to contact our customer chat http://support.t-mobile.com/community/chat
Let us know
Is it the RM-803 model? If so, I don't see that it has the right bands to be able to access 3G/HSPA+ in most locations (AWS 1700/2100) .
TM are re-farming their network so an increasing number of locations can access 3G/HSPA+ on their 1900mhz band, but it may be some time before that comes to your area.