My girl friend gets repeated phone calls at all hours of the day. She used Trap Call and learned that the calls were coming from a Houston number. She made a report with the Houston PD. The calls stopped for a few weeks but now they have started again from a unknown number ( as she no longer has Trap Call) We believe that these calls originated as a result of our bad moving experience from Houston to Spokane using American van lines relocation division out of San Francisco. We believe that this is a employee of theirs doing this.
See if a local lawyer will send a legal letter to this company asking them to look into the matter. Since you can not really prove who it is, I'm not sure how cooperative they will be. If you have the resources, hiring a PI would be a good option. They usually have ways of finding out information.