Deducted a fee for a contract which I did not sign up for

I received a notification from my bank of an amount paid to Telkom, I was surprised as I do not own any product with Telkom.When I called in to Telkom to enquire they informed me I have two products with them, this was scary as I have never been to Telkom. How can Telkom debit my account without me been a customer of theirs?