Rental property wants to put their company sign on our building

We are renting a building the the option to purchase, our lease will be up in one year. We are in the process of opening our retail for our bakery in the front of the building. We were behind on the rent and are now catching up by paying 3,000.00 a week. We have been paying and we are almost caught up. Our landlord has been disturbing/ harrassing us even though we are complying with the court agreement of 3000.00 a week. They have been showing the building, putting signs on out building that it is for sale. Our employees are concerned because they see people walking around showing our building. They told us that they put signs on all the buildings they own. This is all very bizarre to me and am looking for legal advise I don't think I should pay rent on a building when they are disturbing my buiness I will never be able to open a store with a huge forsale sign in it. They are backing them selves by ruining my buiness.note the reason we are behind is because property taxes increased