Maintenance charge being paid, but suddenly demand the same

Dear sir, We are a group of 3 people living in a society. We have been living there since aug 2016. We have a certain amount that is decided for maintainence and then regular electricity fee , both of which is paid by purchasing a coupon from the maintainence office. So the issue is that today suddenly when we went to buy the coupon , the officer in the office has told us that your maintenance was not being cut from the meter since aug to April hence you need to pay ₹35,000. I just wanted to know if there is something we can do as this is not right , coming after an year and telling us suddenly that your maintainence was not being cut. There should be some law for it right? Where were these people for the whole year? Request your support please.