no signal on my phone (sprint)

Have you tried powering off your device for at least 5 minutes to allow it to refresh on the network?  Have you tried manually searching for the network and if it comes up, connecting to the Sprint or T-Mobile network?  Are you in an area where you might be roaming domestically?  If so, try turning on roaming to see if it connects to another network, like US Cellular.  

1. Did you accidentally turn on Airplane mode, which disconnects the phone from all Wi-Fi AND cellular.
2. If Airplane mode is not on, and if Wi-Fi is not switched off, you should still be able to connect to Wi-Fi.  Or maybe there is a problem with the phone. 
3. Have you gone into a T-Mobile store to get your Sprint SIM card replaced with one for T-Mobile? I got mine swapped about a year ago, when they first notified me.  But I think it wasn't absolutely necessary until recently when they finally converted Sprint billing to T-Mobile billing.   
4. Go to any T-Mobile store and they should be able to help you in any case.

Hey there @Easton644 I was wondering if you were able to get signal back on that phone and how you got it fixed. If you could share your journey, I bet it would be extremely helpful for someone else having a similar issue. Thanks :D