Failure to Disclose some of the information to castomers

Good day,

I need help I have a Tracker account where they keep on calling me saying that I owe them money for Cancellation of their Product which it was not explained to that there will be a cancellation fee when I decide to cancel their product.

Today 22/08/2017 I got a call from them demanding again the money and at 1st I told them that I want them to send me the recording where I have accepted when they tell me about the fee but they are failing to produce the recording. Then now they sent me the message saying that my name is now listed on CREDIT BUREAU and Failure to pay may result in Legal Actions.

So I am asking myself now that must I suppose to pay for something that I have no idea of?, if they can send me with the recording where it can clearly states that I have explained the fee to me or signed any document acknowledging the fee then I will pay with no hesitations.

Please help me.