In December of 2015, I got a Samsung Galaxy S6, replacing my iPhone 5. The iPhone 5 sat for a while, until my brother needed a temporary replacement phone. So, I restored the phone to its factory defaults, which unsurprisingly required the phone to be reactivated, but here's the problem: No SIM cards will work. The phone wants a SIM card from the carrier that it's locked to (Fido) and when I place my SIM card in, the phone says that it's not supported, which makes absolutely zero sense to me because it's the very same SIM card that came out of it when I upgraded to my Samsung, and I haven't made any changes to my plan or contract that should constitute such an incompatibility. I took it to the Apple Store and had them look at it. They tried several of their own SIM cards and none of them worked, and they thought that it'd be more expensive than what it was worth to try and properly troubleshoot (the iPhone 7 was just around the corner). Effectively, without spending a bunch of money I neither have nor would want to spend on it, it seems that I'm left on my own. I don't even want to use my old iPhone 5 as a proper phone, I've already got one. I just want to play around with it and have it usable because it was my first proper smartphone, as I had previously used phones that weren't useful for much more than making phone calls or sending texts. Does anyone have any suggestions for me? I'm completely at a loss as to what to do. I don't even know if Fido could unlock the phone, and I don't want to (and can't) pay for that.