What does your lease say: the lease is a contract, and binds not just your original landlord but whomever buys the buidling from them. (The seller can only sell what he/she/it owns--and that is a building where there is a tenant [you] with certain rights; they cannot give the buyer greater rights than they themselves had, which means they cannot exempt the buyer from the lease.) If the lease allows this increase, they can get it; if it does not, the new owner cannot force you to pay it. They can do--and get from you--only what the lease says.