Don't worry about them. They're probably miserable hopeless pricks who wouldn't want to buy the account anyway.
So why not turn the account into an asset for yourself...
Change the name of the account to something like @bestofmiami (or whatever geographic region the restaurant you focused on is located.
Then, go through the yellow pages and start adding images of other restaurants they compete against.
Build the account by ripping every local restaurants followers. Get your account larger than any individual restaurant.
When your account gets big (and you have a niche local audience) hit local businesses up for cash... either shout outs or, better still, daily advertising.
Because it's a "best of" account, you could even hit up local real estate agents looking to sell properties, gyms trying to get new members, smart restaurants looking to put bums on seats.
As long as your metrics are good, there's no reason you won't make cash from daily advertising.
And then you can tell them to f*ck off because you're not a fan of their dogshit restaurant anyway.
Let them retain their "official status" with 12 followers.