Pathetic and unauthorized debit orders

I was at first so excited to purchase 2 beds for my kids in 2022 and the final debit order was scheduled for end of Feb 2024. However on this same day the debit order went off, they went and added admin fees and what more to the account making it that I still owe them. I purchased beds paid for it and the account should be settled after the last installment/debit order.... then they go and add more and more fees making me Liable for their fees which is not fair or authorised as I paid my account in full... This is such a pathetic service, nothing was communicated to me, I mailed them in March to say they are not authorised to debit anything and that the account must be closed. Now again they debited money without my authorisation saying I now owe more!!! Where is the communication... Ive sent a follow up mail and no feedback still. Then they phone me today to say that I still owe them!!! DO NOT MAKE USE OF THEIR SERVICES THEY TRICK YOU AND MAKE YOU PAY EVEN AFTER YOUR ACCOUNT HAS BEEN SETTLED!!! Will NEVER NEVER NEVER EVER AGAIN buy anything where they are involved!!!!! Then this GUY have the audacity to argue with me saying I have not paid my account in full... SUCH BULL!!!! I have kept track of my payments and everything was paid till the last installment!