Threats of jail indicate to me that these calls are by people who have no regard for the Fair Debt Collection Practices Act (FDCPA). Do you know where they're located and the company name? Please consult with a consumer lawyer about filing suit against them for violating the FDCPA, perhaps you will be able to recover your actual damages and attorneys fees and a statutory penalty. In my experience, companies that take this extreme road are impossible to find, then even harder to collect a judgment, because they are unlikely to respond to the FDCPA lawsuit.
If they are getting any of your information from looking at your credit reports, you may be able to find out who they are and stop their access to your credit reports. Below is a link to the National Association of Consumer Advocates list of lawyers, which you can sort by area of expertise. Please note that this law only a one-year statute of limitations and (most likely) the sooner that you sue them, the sooner the harassment will cease. I doubt that sending a simple letter to them to cease their calls will do much, but if you have not done that, then please see the link to my sample letters, below.
Robert Stempler (please see DISCLAIMER below)
NOTICE: The above statements are provided for general information purposes only and are not intended as legal advice or advice of any sort for a specific case or legal matter. If you do not have a signed attorney-client fee agreement with the Consumer Law Office of Robert Stempler, APC ("the Firm"), then until such written fee agreement is provided and signed by both a prospective client and attorney for a particular case, neither Mr. Stempler nor the Firm will represent you nor will they be your attorney in any matter and you remain responsible for retaining your own attorney and for compliance with any and all deadlines and for any statutes of limitations that may pertain to potential claims. Comments made on a public forum, such as Avvo.com, to not have any confidentiality because others may read them. If you desire a private consultation with Mr. Stempler that is confidential, please go to www.StopCollectionLawsuits.com and submit a free eCase Review. The result portrayed for a client was dependent on the facts of that case. Results will differ if based on different facts. The Firm and Mr. Stempler are a debt relief agency. The Firm and Mr. Stempler help people file for bankruptcy relief under the Bankruptcy Code.
California has an entire state agency devoted to regulating the action of debt collectors and can bring criminal charges against a debt collector. So I would start your search for justice by contacting the state government about filing a written complaint. If you would like to seek civil damages to put money in your pocket, contact a local consumer attorney. Hope this perspective helps!
I recommend three things:
1- Let them know you are recording them;
2- Tell them to stop calling;
3- Contact a consumer protection atty who handles FDCPA claims