Do bill collectors have the right to call you at work?

A debt collected can contact you at your place of employment, unless their know that your "employer" prohibits such personal calls {15 USC § 1692c(a)(3)}, which is not the same has the rule covering communications during a time or place known to be "inconvenient" {15 USC § 1692a(1)}. This means that your "employer" must be the one that prescripts that such calls are forbidden, not you.

Now in practice, most collectors if they receive a letter saying that your employer "prohibits" personal calls and they would generally stop trying to reach you at work - even if your lying.

Edit: I feel that the point of this website is to help people and expand knowledge. I do not feel that answers to any questions should include a plug or promote any business or service. I have removed the spam from the answer, and rewrote it so that it is more clear to what the law actually is.