Refuses To Cancel My Cellphone Contract

I got a call from a vodacom consultant earlier this month reminding me that my cellphone contract is ending and that I'll be making my last payment in the month of June. She told me that they are canceling my contract and asked if I'd like to keep my airtime and data benefits going forward and I told her that I'm not interested. This week I went to a vodacom store for help because my phone was blocked and while I was there I was made aware that my contract was still active and that I should call the contract cancelation department to help me cancel it. I called them today and they refuse to cancel my contract and keep insisting that I move to a different plan even though I made it very clear that I'm not interested. The consultant was not happy with my decision and said that they would still charge me in the month of July even if I cancel because I did not give them a notice in advance. Also their consultant is very rude and condescending. I'm very disappointed with vodacom and I wouldn't recommend anyone to take a contract with them.