deposit refund

Mid-city is good at ******ing money from its tenants, and *********** when having to deliver service. Last year I was charged amounts for, late payment, penalty, final demand, SMS fee whereas I never made any late payment or received a final demand from them. I then put a notice to vacate the unit 31 days before the month I intended to move out only for their stuff to acknowledge the notice 12 days later and telling me that it will be considered a short notice and I will be liable for short notice/breach of contract fee, I then extended my notice to avoid the fee. Now it has been more than the stated 21 days to process my deposit refund since I have vacated their unit, but I haven’t received my deposit back even though I have submitted all the required from my side and none of their stuff is responding to my follow ups.