Vodacom bad credit entry

After being a client for 18 year and never missed a payment in Dec 2018 my line was cut, apparently I missed a payment in August. I drew a bank statement and send it to Vodacom but never got a response. Every time I speak to the call center I get a different story. Every month I pay what the invoice states. Vodacom was splitting the invoices and was sending an sms to difference numbers I own. I paid the outstanding invoice and requested to only receive emails, to date I'm still not receiving my invoice via email. My big problem is what I found out this week there is a negative entry on my credit record because of this. This is very disappointing and it effects my credit record.