Hello, I have tmobile 30$ Walmart plan 100min talk, uno text, 5gb of data. I will be traveling abroad for a little over a month and wondering how do i get tmobile coverage overseas? I have to be a postpaid customer right? So, if I switch to postpaid for a month this will fix my problem? Also, I can go back to my 30$ plan when I get back? Thanks for the help!