Unfair business practice and threats

In 2008 I had a contract with Planet fitness and had CANCELLED it in the same year as I was due to study. I had cancelled the contract with an employee who, I was told then left. When I was 21, I started receiving payment calls and sms threats from a company called Saya Recoveries. I had requested two years ago that an INVESTIGATION be done properly as I had cancelled. Yesterday I recieved a mail saying \despite numerous requests I have failed payment\". I had asked them to do an investigation two years ago as I had suigned to cancel and this error is on their side. I am threatened once a year by these debt collectors who have incorrect info. I am now 26. I would like a copy of the original contract and a propper investigation done as I am certain this is ******* what is being done and AGAINST MY CONSTITUTIONAL RIGHTS AS A CONSUMER. "