I'm coming to believe there may be no lower profession than the debt collector. Keep in mind I'm not referring to attorneys who do debt collection. I deal with them on a regular basis and they follow the law. I'm referring to the businesses that repeatedly call and harass the supposed debtor.
I've got a pro bono client now who repudiated a contract. The contracting company is treating her like a deadbeat (and no, it's not okay to treat actual deadbeats this way anyway). They call her repeatedly, literally on a daily basis. This after I've sent them several letters instructing to direct all communication to me.
The last guy I talked to was a flat-out liar, and an idiot to boot. This must be a great industry for felons who are looking for work, because these guys have no standards whatsoever. A felony record is probably a plus on a job application.
The good thing is, if you're a lawyer who's comfortable with this stuff, these guys blow over like fine paper in a hurricane.
It can also be frustrating for people to get a debt collection letter. In my own life I've had a few disputes with companies where I refused to pay bills for good reasons. Rather than engage in a genuine discussion with about how to resolve the issues, some companies will just hand it off to debt collectors. The debt collectors will then send annoying letters and make harassing phone calls to the consumer for years.
In general I try to ignore them. If they're calling I'll mail a letter instructing them not to call me again. Then it gets handed off to a new debt collector who apparently is not bound by the earlier letter. That's one of the games they play with the Fair Debt Collection Practices Act.
If the debt is small enough, they're probably not going to sue (but there are exceptions). When you refused to pay for a valid reason, the lawsuit is what you've been waiting for because you can explain (calmly) the reasons why you refused to pay and why it's not a valid debt.