No communication

I had a vodacom contract, and on emailing vodacom and calling them to cancel the contract. I finally managed to have it canceled. Once this was done they switched me over to a data only package with a debit order on my bank. I then requested for this to be canceled after 3 months. Till to date I am still receiving an invoice from vodacom stating that I owe them R64. Even though my account was on a debit order. After numerous emails to vodacom and with no replys back my credit score is now in the red with missed payments.

I need my credit score back to a positive position.