What to do.. What to do...tmobile

Been with T-Mobile got 10 years +. Bought a 640 on launch day and LOVE my phone. I have insurance and have a crack that I'm sure will cause issues down the line..... Insurance can't replace because of them having nothing on Windows..... Which truly upsets me. Do i buy a pre paid phone version? I'm open to any phone equal or better that is WM10 capable, but I'm tired of zero support and options... Anybody got any advice?