Last year bought an unlocked ATT Galaxy S4 from ebay, worked great, used my T-mobile SIM. Had a fluke screen shatter incident, sent it in to Samsung to get screen replaced. Didn't realize they would flash it to the point that it locked the SIM. I requested they unlock it but was rejected because they claim the phone is activated on someone's account. Now it is useless to me. I checked the imei on swapper and their system said it was likely not blacklisted and was likely clean. Hmm. If I can sell it that would help ease the pain. However, I fear that if I advertise it as ready for an ATT sim, I don't know it if it will actually work since ATT said it was already active on someone's account. Advice? (hopefully I'll get a few serious answers--thanks)
Thanks in advance for those of you recommending I get an iPhone.