Atrocious Business

So after countless back and forth a with this completely preposterous company for a balance owing on my business account, I receive a settlement letter with an amount I am needing to pay. A payment is made withing an hour to say the least, and my assumption is that I was done with that. Fast forward 2 months, and I start receiving threatening texts saying there is an amount outstanding on the same account which astounds me as to my knowledge I have paid it in full. Dated. Email received. Settlement letter received and signed.

Then for some odd reason the bank debits me for this apparent outstanding amount, not once, but twice.

The response I received from this ridiculous I'll advised consultant at this so called firm, "we didnt calculate the proper amount due to blah blah blah excuses excuse excuse"

I have said it before and I will say it again, that has absolutely nothing to do with me. That is between your firm and FNB who has outsourced you. You cannot keep the client liable for a mistake carried out on your part.

Documentation and email correspondence is in order for the payment and the settlement so to debit my business account for interest and whatever else owing, without warning might I add, is completely unbusiness like behaviour to say the least.

I will not, and one should not, take this laying down. Enough is enough. If someone in a senior position does not make contact with me somehow, rest assured I will be taking this as far as possible.