I turned off find my phone to do a restore and now activation lock says it belongs to someone else, HOW?

I bought it over a year ago used and unlocked. When I bought it, it was totally clear. I went through all the steps to set it up with my Apple ID and password and I have been using it all this time with no problems. I never had a SIM card and was just using it for a wireless device at home to check email. listen to Pandora, keep an eye on a security camera, check the weather app and I even added a Magicjack app to make phone calls from home. The reason I was trying to restore it was because I realized I could activate it with a cheap Consumer Cellular account. They couldn't get the their SIM card to work so as a last resort they told me to try to do a restore on the phone. Now it's totally locked me out and says it belongs to a different Apple ID. How could this happen after I set it up myself and it let me turn off Find My Phone with my Apple ID? Does that make any sense?

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