What is the procedure to complain against the cooperative housing society’s secretary?

I own an apartment in a complex in TN. The MC(Managing Committee) of RWA (Residents Welfare Association) manages facilities through Contracts & Staff. Expenses for these are payable after completion of the month. MC has enough bank balance to cater to monthly expenses. Maintenance charges (Rs.3,000) for the month are payable before 5th. For payments made between 6th to 10th, the penalty is Rs.100. For payments made after 10th, the penalty is Rs.200. Above terms have the approval of the general body. Queries are: *1.Is it permissible to demand charges for any month while the services get completed after the end of month. *2.Penalty terms appear abnormal / unlawful. Pl advise.