Charged for NO service

Line not working, still being charged - please help I have been waiting over 6 months for my line to be fixed and my account credited. I continually get charged and cannot get any assistance from the website, emails or call centre. This has now resulted as me being listed as a delinquent payer on the credit bureaus. I refuse to pay for a service I cannot receive yet telkom still charges me fees and interest for no service.