If you've been getting harassing calls from debt collectors, you can fight back by recording your phone calls to catch them in the act and prove they've violated the FDCPA. Depending on what state you live in, it may or may not be legal to tape-record your phone calls. Minnesota is a one-party consent state, meaning that you can record a phone call without another party's consent, as long as you are one of the parties to the call (you can't record a call between two other people). Your cell phone may have a recording feature. Otherwise, you can buy a telephone tape recorder for a pretty reasonable amount of money.
There are two types of recorders we've used in the past. One is designed for landlines. It has a telephone cord input and output, and you just run the phone cord in and out of the device. Here's an example.
The other is designed for cell phones. This is an adapter that plugs into a regular recording device. It comes with an earpiece that you insert into the ear you're holding your phone up to. It picks up both ends of the conversation through the sound coming out of the receiver. Here's an example of one of these.
Even if you live in two-party consent state--one where you are not allowed to record calls without the other party's consent--here's a little trick. You know how debt collectors sometimes play a recorded message saying "This call may be recorded for quality purposes?" Try using the very same line on them. If they don't hang up, you can feel free to tape away. At the very least you may confuse the caller too much to give you any trouble.