Question: There is a particular recruiting company that continues to contact me. I have been unhappy with their performance in the past and have been clear that I am no longer interested in their services. I have had to inform them of this multiple times.

Whenever they contact me, I inform them that I do not want them to contact me further. They oblige for a few months, and then I get an e-mail or phone call from a different recruiter with the same company. Most recently, I expressed my frustration and insisted that I be completely removed from their database. Today, I received another e-mail from them after months of silence.

Is there any sort of legal grounds I can quote or anything else I can say or do to force them to *actually* remove me from their list of contacts and stop contacting me?

Answer: 
Unfortunately you've already violated the cardinal rule about dealing with recruiting companies:

1. Never, under any circumstances, give a recruiter (or anybody else) that you do not personally know and trust your phone number.

These people are tenacious, and many of them won't take no for an answer. It's best to deal with recruiters on an e-mail only basis (or not at all, if you have that option), since at least an e-mail received at 7:00 am isn't going to wake you up and since it's easy to set up filters for recruiters that can't take a hint.

Once I made the mistake of posting a resume containing my phone number and e-mail address on monster.com. The next day my phone rang about 2 dozen times with calls from various recruiters. The day after that I took my posting down, but the calls continued for months afterwards. And years later, I am *still* getting a few e-mails every week from these people.

Anyhow, in terms of what you can do about it, your legal options will depend upon your location. In the U.S. there is a national 'Do Not Call' registry. I'm not sure how/if that applies specifically in the case of recruiters, as there are a [number of exceptions](http://en.wikipedia.org/wiki/National_Do_Not_Call_Registry#Exceptions_to_the_do-not-call_rule) that exist. You can check with a local lawyer and see if they can come up with any other options.

Or the next time they call you, just calmly inform them "Look, my phone number is on the national do-not-call list, and I have repeatedly asked your company to stop calling me. If you continue attempting to contact me against my wishes I will have no choice but to seek legal action against your organization." That ought to resolve the issue.
I've been a recruiter for almost 15 years, and hearing stories like this make doing my job much more difficult (gives the impression that ALL recruiters act like this, which they obviously don't). [aroth's note](https://workplace.stackexchange.com/a/3733/168) about not giving recruiters your phone number is one option obviously, but many recruiters will respect your desire for privacy. I almost always use email to contact candidates initially and for 'check-ins' occasionally, and generally only make calls when we need to discuss some specifics (beginning of the relationship requires screening candidates by phone, but once I know you pretty well we can handle most of our interactions via email).

I think in this particular situation, 'outing' the recruiter and company might be something that could get their attention (assuming you have some platform to do so). A recruiter's reputation is incredibly important, mainly because the recruiting industry has such a poor reputation overall that people simply assume you are unethical until you prove otherwise (guilty until proven innocent). I know I would be horrified if a candidate posted my name in a bad light to others in their network. That kind of thing might get their attention. Twitter, LinkedIn, Facebook, user groups or professional organizations could all be places you could at least threaten to go public if they don't discontinue their actions. 

The chances of you suing them or pressing charges that would actually hold them accountable are probably low, and they know that. The only real thing you can threaten is their reputation.