iPad activation lock

Is there anyway I can unlock my old iPad mini that I gave to my grandmother about two years ago. The iPad was registered to my old iCloud account that is currently disabled. A few weeks ago the old iPad mini had an activation lock on it requiring that I sign into my old iCloud, because someone used find my iPad, but I could not because it’s disabled. I don’t have any proof that I bought it because it’s been years and I received the iPad mini as a gift between 2012 - 2013 and I threw away the original box and receipt back then.