A run around with my deposit refund!

Besides cracking buildings and electrical faults, they are doing a run around when it's time to pay back my deposit, inspite of giving more than a month's notice. With 3 calls and 2 emails, they told me (a week after the 14th of February, which was the day for my deposit refund), that they can't read my bank confirmation letter. On the 18th they had said the bank has a problem with making payments. Then, on the 23rd, after I made 2 calls on the day, they said they can only process my refund on the 14th of March 'cos documents were not clear! Why didn't they pick this up when the said documents were submitted, before all my calls, before the bank had a "problem", before my emails??!!!!