Pensioner's nightmare

I had a contract with MTN for over 10 years, all of a sudden I started noticing huge billings going off my account totalling to R19800 when I enquired I was sent from pillar to post with no one giving me a lousy statement to account for this billing till this day. I was given a reference number, no report for an investigation nothing. Just because I am a pensioner I have been tossed aside and told to go cry a river by their consultants when I went to the local MTN shop! I'm mad for being billed almost R20000 for what they say is data but nothing to show me to see. MTN get to the bottom of this and give me proper customer service as old as I am, my money is not old! You enrich your business with ********* conduct sies maan!!!!!