Yuzi download

I bought an s6 active off of eBay. When I went to boot it up everything was fine till I got to a Samsung account lock. I dont know if its appropriate to ask but does anyone know how I can use my own account. The person I bought it from says they are a pawnbroker and they can get the info or talk to the person to remove the device from their account. If you can help awesome, if not I understand, if you can point me in the right direction cool. I would contact Samsung like Ive done in the past but I cant even get the imei from it. If this is not an okay post please delete it and pm me so I dont make the same mistake. Thanks much