Sold ipad locked

I sold an Ipad 2 that was my wifes on ebay. Before selling I restored it to erase everything on it and got to the Hello screen. As I stated I sold it and the person I sold it to states it is locked and needs me to remove it from my device list. I found it under my wifes itunes and removed it. He emailed this morning and it still is locked and says its attached to an gmail account I no longer use and has been closed. Is there anyway to unlock this ipad?