FNB debiting for loan insurance: Unfair!!

I really do not understand why FNB is still debiting my cheque account for an insurance on my loan. This is after I sent them the Cession documents to use my current personal life insurance I have with another Insurance company. The documents were sent to them on Monday 21/07/2015 and on the 26/07/2015 the debit order ran for my loan instalment and it included the insurance fee. That is really unacceptable and I communicated this to FNB when I took the loan that I will be using my current insurance to cover the loan. I have already been debited for 3 months for this insurance which cost me more than R400 per month. This is unacceptable and please refund me for this it cannot afford to pay for an insurance double (i.e. current insurer and FNB). <div><br></div><div><em>(Supplier name changed from FNB Insurance Brokers to First National Bank by Hellopeter.com)</em></div>