Locked into a contract that I didn’t sign.

I have a business account with Telkom Mobile. Just over a year ago, I went to a telkom direct store in Port Elizabeth and bought a data sim and asked for data to be loaded on to that sim on a month to month basis and link it to the business account. I was told that I could cancel that at any time. I did not sign any contract. Since then I have moved to Johannesburg and now when I want to stop the month to month data, I am being told that it is a 24 month contract and if I want to take it further I must go to the shop in Port Elizabeth to rectify the issue. This is pure ********* and Telkom trying to squeeze their customers for all that they can get.