Cancelation issues after 2 years.

After 2 years I want to cancel 2 of my contracts with Vodocom. After numerous conversations and explaining why I want to cancel these 2 contracts, they just ignore my request and changed it to prepaid. This was not wat was discussed and also not what I requested. As per their explanation it will be better and I will not pay anything. I did not agree to this change as I want to contracts cancelled. I had it for two yeas I don’t need it anymore. As per their rules I had to phone them, give them 30 days’ notice which was done, spend hours on the phone explaining why they must cancel these contracts. It was a 2-year contract it is over 2 years now, why must the client now beg and convince Vodacom to cancel the contracts. This morning I received an invoice from Vodacom on both the contracts. Is this just incompetence or a way to make money without the client agreeing to it. I am also reporting this matter now to the ombudsman as Vodacom can not be allowed just to make and do as they please.