Where are my SMS's and Data (2 months in a row)

2 months after upgrading my cellphone contract i am battling to receive my sms's as well as Data from MTN. Everytime when i call the customer call-centre i am told that it will be fixed in 2 - 5 days and to date i haven't received my sms's and data as per MTN's obligations. They are quick to debit my account and without fail for R729.00 Per Month but very slow to fulfill their obligation. To make matters worse i have requested for my monthly invoice and was told that i have to pay R18.00 and i said \NO I AM NOT PAYING"because the service is included in my statement/invoice"