Poor service

So in September 2023 was advised by an agent at multichoice that my decoder is old since I was having problems with it, I have to buy a new one.I bought a new and it was activated and linked to my profile and everything was fine. Now in March 2024 after paying my normal subscription, that I have been paying from September 2023, my services get suspended because I owe DSTV for my other decoder (apparently I have two decoders active). It's been active all these months, but am only being charged for it now, how come?