BAD SERVICE FROM VODACOM

Complaint: Bad service from VODACOM. I upgrade my contract with Vodacom on 3/4/2020. I suddenly decided that it's not good for me then I decided to cancel it on 6/4/2029. Vodacom refuse to cancel it. I kept on calling Vodacom often. they promised to cancel but they never did that. I am now putting complaint against Vodacom. They kept saying they will contact me. I don’t see any progress with regard to my contract with Vodacom.?