Unable to upgrade

So Cell C says they will not allow me to upgrade due to my credit score. I have two contracts with them. This past April they allowed me to upgrade my one device R20 000 device, then they did nor care about credit score. But now they are singing credit score.

So my 2nd contract is on month 20 now, effectively ending November, I have not missed a single payment with them over the years, on the contrary they messed up my account by only allocating a payment that was made in November they allocated in March but that's a story for another day.

So i asked the retentions lady if Cell C says they won't give me an upgrade that's obviously means that after November I can expect not to be billed since they have already decided for me they won't upgrade me, she then says no I will be billed month to month since never canceled. Now my question is why on earth would you want to keep billing someone until they contact you when you already decided you will not upgrade their contract? I asked her if I dont cancel for 5 years my account will be debited for 5 years after my contract has ended already but on a month to month basis, my question is why would you want to take my money since I am not worthy of an upgrade? Should not the owners be on you to stop debating me as you already said you don't want to upgrade me?