Not fair and ethical when dealing with vulnerable people

My father received a call from DC Payments Solutions, after a call he realised that he was put on the debt administration.

He then immediately contacted DC Payments Solutions to cancel. He was told this was going to be cancelled but they want him to pay R2903.75.

He want to cancel this debt administration because he did not sign up for it knowingly. He also does not want to pay R2903.75.