SIM card

So what you need to do is turn that device off, remove the SIM card, write it down or take a photo of it then call your provider and have them activate that SIM card for you. Now when you say locked, do you mean a carrier lock or you don’t know the code locked?

If your phone is locked to a different carrier, you will need to contact that carrier and ask them to unlock the phone.

Who is your service provider?

You’re more than welcome! And of course the device has to be paid for in full before they will unlock it so no monthly installments can be on that device to request a device unlock just so you know.