Vodacom milking innocent users

I was retrenched in 2018 March and I had a contract with vodacom. Since account was blocked I discarded my sim card. In 2020 October, I paid-up my account (R1 700.00) and I never used the number again. I was surprised to learn that I now owe R2900 of services I never used. I was told the account was reinstated automatically after being paid up and to my surprise, I never received any notification nor any invoice or statement, like I previously used to. How was I to know that the account was reinstatement if Vodacom did not send me any invoice? I am not going to pay for NON-SERVICE and I have decided to cancel all future business with Vodacom.