I received an iPad with an activation lock.

As part of a purchase, I received an iPad that used an app to control other hardware (also in the purchase). The iPad was setup with an activation lock by one of the developers using their personal email - not the companies email. It's been some time, and now, I can't remember the password - to enter the iPad to use the app.

I did a restore, and I can re-install the app when it's done, but now it's asking for a Gmail account from that dev person that I don't have, to remove an activation lock.

I no longer have contact with the original point-of-contact person there, and neither does the company I purchased the hardware from. The dev person that originally setup the iPad with their personal email no longer works there.

So, now how can I do a full factory reset?

This is very frustrating.