Is what our landlord doing legal?

Our landlord is charging us more rent because we have the only unit with a gas fireplace.Everything else is electric.The gas fireplace doesn't work in fact the gas records say due to safety reasons it has been out of service for years.The land lord told us it worked. Before we moved in we were told pets were allowed,When we asked what would be the deposit on a 1 gallon fish tank and were told 100.00. After we moved in we were told no pets allowed.We told a family about a open apartment in the building they were told children are not allowed in the building.We found that strange seeing as some of the other apartments have kids. The landlord wants us to pay late fees we have already paid.