Bad experience with Vodacom

I took out a A2 core Samsung with Vodacom in 2019 everything was done telephonically of which was delivered to me via courier , the amount per month was R129 for 2years of which was deducted from me every month of which i never received any written contract or any statements while paying the phone off so when the last debit order was deducted last year 25th August 2021 before the last payment i got a call asking if i want to upgrade i did say no, so end September 2021 Vodacom deducted from my account a R150 of which i reverse cause according to my understanding the phone was paid- up and nothing due to them it happend again the following month where they deducted R300 and odd from my account so i reverse it again , so i took it upon myself to call and findout what was the reason that they still debit my account the lady that assisted me explain that she cant find any details of mine on the system and am i sure that i have and account with them cause its strange that nothing appear on there system , i didnt suspect anything as she wanted my details of which i gave i also explain that i didnt use the airtime as i did change to cell C and that i also didnt receive any paper work nor statements from them, with my luck i was handed over to their lawyers VVM harrasing me for not cancelling my contract and thet i owe Vodacom R550 that i need to pay i aslo did explain that i didnt receive any contract from them and but they want their monies , i feel really disgusted with the treatment im getting , why dont the pick on people that owe them thousands of rand for non payment of ietms , so im getting phone calls for a contract that was'nt cancelled I cant even remember what was said on the phone and if i did get it on black and white i was going to remember to to cancell the contract as it was the first time i took out a contract cause i usall buy phone 's on COD.