5 SIMPLE STATEMENTS ABOUT OPPO レノ A EXPLAINED

I bought a 2nd-hand telephone and when I needed to reset it, it requested for a password which I don't know. I checked the IMEI to determine if the cell phone was stolen and no, It is far from stolen, but it surely does have an outstanding debt with the corporate AT&T. So, I don't know what to do due to the fact I don't even have the cell's Bill.Wh