As I can understand from your explanation, the property that you have bought might be considered as a turistic apartment, which means you can not rent it as the common properties in Spain. In such case, you (or your advisor) should have a look on the turistic Spanish legislation to know how are you allowed to rent it. In general terms, you must be a turism professional and apply for certain licences. But the national legislation is pretty limited and it depends more on the regional and municipal ones (so it depends on where your apartment is located).
I have recently read an article on the Sunday Telegraph about a lady which owned a turistic apartment in Mallorca and had rent it privately. The authorities punished her with a 30,000 € penalty and had to instruct a solicitor to try to reduce it! (as the Balearic Legislation states such penalty).
Secondly, regarding the Community fees it is a common practice that the Community Association sets up as a turistic professional in order to manage with the required licences and rent the apartments by yourselves (instead of paying someone to do for you), and might be the reason of an increase on the fees. But obviously you should check this in your Community Association, it is possible that it is not the case.