Vodacom refuse to cancel my data contract which is out of contract

My data contract was finished and I decided that I’m not going to renew the contract because we have uncapped Wi-Fi at home. Somewhere beginning 2017 I wanted to cancel my contract because I was out of my 24 month. I could not cancel it because all of a sudden my account was in pre legal. Well I paid 3 April 2017 R327 to get it out of pre legal so that Vodacom could cancel it.... The took my payment and never cancelled my contract - now 6 month later I’m in pre legal again and before they will cancel my contract I must pay R425 again. How many times will I have to pay to get this data contract cancelled? Really Vodacom’s service is the worst and I will never do business with you again or would never refer anybody to them