Virgin Active Service is HORRIBLE!

I cancelled my contract a few years ago (2016) and made arrangements for payment of the cancellation fees, etc. A few months after that I received a call from a debt collection company stating that I still owe Virgin Active R414.72 in total. I paid the amount before the "cut-off" times they gave me, since I did not have a problem to pay them if I owed them like they stated. BUT NOW TO THIS DAY I keep receiving calls from the debt collection company, VVN, regarding ANOTHER outstanding amount of R357, everytime I have to work with another person and explain to them that I've paid the original amount and emailed the POP again and again. The last time they phoned me in January I had to go through this entire exercise once again and they sent me an email to say they've received the POP and it has been escalated only to receive a call one again this morning with the same issue?! This is ridiculous! When I request to only work with ONE person and to get the direct email I'm told it is not possible, but working with the general email and centre also doesn't lead to any solutions?! I am very frustrated, since they keep calling after I requested to only communicate via email so that I can also have records of everything but now they start calling at my work place as well. This is horrible service and it's sad that a company this big has a few *********** staff members that cannot do their work properly, because if they did do it properly people like myself would not have to deal with unnecessary situations like this! I would not recommend any one of these businesses!!!