New purchased doorbells

I purchased a ring video doorbell brand new in the box with paperwork such as installation. Purchased at a swap meet the package had been opened but was a legitimate sale & purchase. The Ring people tell me it has an account on it already. I have no way of finding out who tried to activate it prior to me and they want me to buy another one. Why can’t they contact whoever to have them sign off on this one? Or if it was stolen I will return it but nobody her will buy another, we can’t afford it!

It’s not Ring’s responsibility to go hunting for the owners of devices.
As you found, that’s the problem with buying goods from non-authorized dealers. If you had done that you would have some recourse with Ring.
All you can do is take it back and hope the swap meet vendor will give your money back.