I understand, is why I stated the last part.
I haven’t tested out all the options yet, so excuse me if I sound ignorant, but based on the OP’s original suggestion, I think a toggle for if a listing or listings (as a whole) should expire or revert from a paid to a free version would be a useful. I assume theirs limitations, but by no means am I a coder or anything of the like. I’m great at research though haha… Have a great day!