Hot answers tagged internet
It sounds like your phone is SIM-locked: https://en.m.wikipedia.org/wiki/SIM_lock This is imposed by the operator you bought the phone from, and has nothing to do with Poland. Contact your home operator and see if they can unlock it for you. This is usually a paid service.
It sounds like your phone is Blocked in Poland ie reported as lost or stolen: Blacklists of stolen devices This has nothing to do with your provider, your phone(s) might work without any problems in other countries. If your phone(s) was/were SIM-Locked you would get a different message before loading the home screen, something like the this I am afraid ...
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