Matrix keeps debiting account after cancellelation

If I can give zero stars I would.

Matrix beami keeps adding monthly fees on my account after 3 month payment arrangement was made for cancellation settlement. During this time, although I made manually payments they still listed debit orders. Mid July I noticed by sms that I owe R200 more than the actual amount / last instalment due end July. I paid the full amount outstanding and emailed proof of payment. They then added another R97 rand after I settled my account and tried to debit my bank account. Today I received another sms to say I owe R97. The call center insist I must pay this amount and dont understand when I say I settled full amount prior to them adding another monthly fee. I am so sick and tired of matrix beami just adding amounts! How do I get them to close my account and delete my bank details.