I purchased a system from XXXX XXXX as a free trial for {$24.00} and returned it to the merchant before the trial period expired since the merchandise was defective. The merchant never returned the initial amount of purchase but then charged me for the next month supply ( which I never received ) as a recurring fee of {$69.00} and I disputed the transaction and told them I have already returned the system and they should n't be charging my card with any recurring fees because I wanted no business with them. All I know after that I started receiving calls from a collection agency named Monterrey from which I have never received any mailing stating why they are charging me the amount of {$590.00} reflected in my credit score or how to dispute this transaction. They are harassing me with calls at anytime, even when I have told them to stop calling me at work, they got my house phone number even when I never gave out this number and have n't stopped calling me since. I called the original merchant for an explanation of why they are charging me that amount when they have the system back and they just blew me off telling me I need to talk to the collection agency. I 'm seriously considering a civil action against the XXXX companies for unlawful business practice ; they are charging me for an amount they have n't disclosed in detail why I owe them, then harass me at any given time they feel like calling me, I have asked them for a detailed explanation of the " debt '' and as a consumer I have not received any plausible explanation of this so called " debt ''. It 's been a year since I first purchased this merchandise and returned it, and it 's getting to the point that they are ruining my life with this issue, they will wake me up my sleep with calls. Please help me with this matter, I do n't know what else to do. Thank you.