Double debit without warning

I increased my monthly debit order on my pension fund. After 2 months i realized that the new debit amount still hadn't come off. i took it up with my broker and he said he had in fact submitted the documents to increase my debit order 2 moths ago. on the 27th of November they double debit me for the two months that they never debited my account. They gave no warning. They couldn't even phone me to make arrangements or to commence this increased policy at a newer date to avoid a double debit. I wake up on the 28th and my account is in minus of R1500. Today (29th) the whole amount is credited back into my bank account and ive been charged an extra R90 for unpaid magtape.