MTN ZTERouter pillar to post

My name is JB Makoanyane I'm very dissapointed with the mtn, I bought a mtn router ZTE MFR86C white colour online in April,it was just a router without a sim and I returned it 06/04/22 n April at South gate and I was assisted by Monde who told me that everything was fine and cancelled the router. 3 months later I'm receiving an SMS from MTN stating that your services stopped in 1 day and you'll be reported to a credit bureau if MTN doesn't receive payment of R 1952.47,what **** is Monde and MTN running because I'm really confused. I went again to MTN store at South gate mall today 24/07/22 and I was told to call 135 to cancel, cancel what because this was cancelled 06/04/22 by Monde. I'm very disappointed