Stage Zero incompetence

I had a UPS which was supposed to only be on contract for 12 months with VOX. The contract was then taken over by Stage Zero. I cancelled the contract in May 2024 as I felt I had been misled by VOX as I was under the impression that the contract was valid for the 12 month period and I would then own the UPS, but this was not the case and Stage Zero advised me that the UPS would be on contract indefinitely. Mail confirmation was received that there were zero outstanding monies owing, which I still have mail proof of. Mail arrangement was done to collect the UPS, but nobody ever collected. I also have all other mails as proof of cancellation, etc. The unit has been languishing in its box in the cupboard, waiting for collection since May. Received a mail on Friday 8th November with attachment advising me that I owe Stage Zero R499 for Non Returned Stock. Sent them a return mail with proof of cancellation and last payment made in May, but no response has been received. Saturday morning my account is debited with R499.00. Tried contacting them, but offices closed for the weekend. As far as I’m concerned, this is theft and I want my money returned to my account. How do they access public bank accounts months later with no phone calls, communication or explanation and misappropriating people’s money like they have done to me? As far as I am concerned, this is totally ******* and if the money is not paid back, I will be reversing this charge at the bank. They are also welcome to arrange collection of the UPS at my convenience.