Over Charge bill, report with no help or feedback

I have for years an cell phone contract with Autopage Cell C. From This year my account is in suddenly sky high. When I query it they said is data. I immediately log a call and said is impossible because the phone I use is an old Nokia phone that has no internet connections. I also put a call limit on the contract. But with no luck the bill is this month double the limit. For the last few months I phone, went to the store Write letters, nothing helped. How can an company not care for their loyal clients. My ref: no 640417. If someone can give me an contact number who I can phone to assist me with this problem. Autopage contract end in November, so I am stuck till then with them.