Claiming city

[patatopatathoe]

Hey,

so, i made a region in the multiplayer option, and i claimed two cities, others have claimed the rest of the cities. but they abandoned it. So i tried to claim it and it says it has content i do not own, is there any way to just delete the city or delete those things or maybe its a bug cause every time i try to claim a city is says that. 

any solutions?