I would start with fully reading your lease contract and if you can't understand it you should contact an attorney to help you better understand your lease. Your header was can they charge for things they invite the answer is NO they can only charge you per the lease contract and if for some reason they operate outside the lease they are in the wrong- but its like this if you get an attorney involved be aware of the beast you might awaken if they are this bad and you haven’t got on the bad side. Honestly and I pray you don't take it the wrong way in today’s market if you pay on time and your not the problem most landlords are very forgiven and to anything to keep good tenants so for some reason it sounds like they are trying to run you off or someone in the office is trying to look good for the bosses by whipping a tenant into shape so to say I HOPE THIS HELPS AND GOOD LUCK

Another thing why rent when the government has special loans for low income families where they subsidize your payments