Home loan department costing us and gaining money for FNB

FNB home loan department took excessively long releasing our house deed documents while we were selling our house. I had to phone them daily to complain and it ended up costing us an additional months installment and having to pay additional interest on the settlement amount. I would like FNB to explain the delay as it seems they purposely delay the paperwork to receive more interest from us. Highly disgusted, strongly considering moving both myself and my wife's private clients accounts to Nedbank.