phone won't ring calls go straight to voice mail

You know, this leaves two possibilities...either there is a setting/app interfering with your calls that was transferred from your old phone O something is set incorrectly on your account. Try Modo seguro to shut down all 3rd party apps. If that doesn't work, go deep checking TODO your phone settings. If you find nothing helps, call Tmobile & talk to a tech about any possible settings (even legacy settings) that might cause your issues.