This may influence how and where their products appear on our site, but vendors cannot pay to influence the content of our reviews. We may be compensated by vendors who appear on this page through methods such as affiliate links or sponsored partnerships. Jack Wallen walks you through the process of adding a SIM PIN to help prevent anyone from accessing precious account information or using your data plan. T-Mobile also locked the phone I use qlink wireless with.Pro tip: Protect your Android SIM card with SIM PIN lock I can't seem to connect with the unlock device app that was installed on my phone. I put a textnow sim card in my unlocked Galaxy S10 and T-Mobile locked it. I would really like to know if anyone else has had experience with a device that was definitely unlocked and used elsewhere, then shows as sim locked again, as even tech support told me they'd never heard of that happening. Is there any way this could still somehow be the reason it is locked again? I know this would impact getting a device unlocked now, but again, her device was paid off, unlocked, and used on another service years ago, long before I even left T-Mobile. Obviously, this left my closed account in bad standing with them.

The billing cycle was after I had terminated service, so I refused to pay it. When I left T-Mobile myself, they sent me a bill after my service was supposedly shut off. I thought it was impossible to relock a phone? I know the device was legitimately unlocked before, as she has been able to use it on a different carrier this whole time. Verizon support says that her device is still locked by T-Mobile, and her settings do say it is sim locked. The new SIM however gives the message that the 'sim is not supported'. Her device showed as compatible, so she was sent a new SIM and had her prepaid service shut off. Recently, she switched service to Verizon. For several years since, she has used the unlocked device with a different SIM on a prepaid Walmart plan through Total Wireless. After her device (IPhone 8) was paid off, we went through the entire process of having the device unlocked. I had an account with T-Mobile a couple years ago.

The sim card has locked