VODACOM FIBRE FAULTY BILLING

I am disappointed about Vodacoms billing, you get consistent sms to say your fibre account is in arrears, when you call the number on the sms, the call centre agent told me its outside the accounts departments hours. These messages was an influx on a weekend. Then i also get phone calls from an automated voice to say i have to make arrangements to pay my account. I dont owe Vodocom money for my fibre account because the cancelled it and told me they wont charge me. Ive done everything they ask, still they bill me and challenge me to terminate my service. They billed me for 2 months after i do not have service, each time i call they say they will get back to me, instead i get sms and calls to say my account is in arrears. I was even unable to do a sim swop over the weekend as my account according to vodacom is in arrears. Thos is unacceptable Vodacom is nou causing for negative reporting on my credit report based on their errors. I dont know how to stop this.