Vodacom charging me for services that Iam not using

I have such bad experience with Vodacom. Had a cellphone contract with them. last year September I was due for an upgrade, I didn't go for the upgrade this lady kept calling me to give me options of what I can take. eventually I said I'm no longer interest to take a phone so the should cancel my contact. Come month end they keep deducting. when to a Vodacom shop spoke to a lady she said she will query the cancellation for me. Vodacom then decided to block my sim. during lockdown I've been trying to get hold of them with no luck. my sim is still blocked and I see the bill is still going up every month and they haven't been deducting from my account. on their Vodacom app it says I owe R1611.96, bill so far: R219.99 airtime: R438.28. It's been so frustrating. my question is that amount that keeps going up what is that for because I didn't take a new phone, I can't make calls?!!! Really this has been so frustrating. Is this how they treat people?