Joomla Website Design Software. You should also check that your phone is working with an original network SIM card because, if the phone is not, it may have been reported as lost or stolen and will not work with a network. Simply put, if you bought your phone through a carrier, either in a two-year contract or a monthly payment plan, the phone will not be unlocked technically, even if it supports other carriers. Cellular technology is a bit complicated, and while the transition to a single standard has for 4G Using a device between all four carriers in the US is still a bit difficult. This is in sharp contrast to T-Mobile bitterest rival Verizon, where you can always use an unlocked device on any carrier, regardless of the remaining payments on the device. If you have a prepaid or pay-as-you-go plan, your iPhone is probably unlocked. Where Can I Buy An Unlocked Iphone 7. However, if you have a two-year contract or something similar, your iPhone will probably be blocked by the wireless service until you pay it off.