Debit Order still going through

In July this year I phoned the Head Office to get the full amount outstanding on my son's contract which was due to expire in December 2015. The reason I phoned was to get the exact amount and not to make a mistake. I then paid the amount and emailed and faxed it through to the head office as requested by them. I then received an email saying that this account has now been closed. However, two months ago I was debited with an amount of R69 something. I contact them and was advised that it was for a late cancellation I was suppose to give three months notice!!! I said that I had already cancelled in July and this is September! Nothing transpired and then this month on the 1st an amount of R249.00 went off my account! I have emailed them the only response I get is that this account has now been closed! I have phoned but have not gotten anywhere! Is there anybody that can help me please? I am so frustrated with them after having been a customer of them for more than 10 years and this is the treatment I am getting!