Clearance certificate a nightmare

I have settled all my debts in September 2020, when I request my clearance certificate I was told that I have outstanding balance still to be paid, and this came as shock to me as the amount they claim I still owe is triple the amount I was originally owing. I don't understand why should we get this kind of treatment afterall, tickets are being closed unresolved and they will claim that your matter is being resolved, I have trusted this company since day one I joined them till when they showed me where to get off, I am so embarrassed with the service they offered me lately, it really showed me that they don't respect their clients...rather they bring stressful situations into our lives.