Was there a fine associated with the "warning"? If collector is trying to collect that fine, then most likely not a "debt" subject to the Act. But, it wouldn't hurt for you to send the collector a cease and desist letter, or ask for validation of the debt (how much? who's the original creditor? where did this debt come from? etc.). All that said, you might want to contact a consumer protection attorney for an opinion. You can find one here: www.naca.net. Good luck.
The above is for informational purposes only and does not establish an attorney-client relationship.
I am not aware of anything that would exempt a debt collector from the provisions of the FDCPA. And I am not aware of too many situations where a statute of limitations does not apply to a personal debt (student loans would be one exception; another may be monies owed to a state/federal/county government because "time does not run against the king.").
I am wondering whether you need a traffic attorney rather than a consumer/collection attorney.
Assuming that this was a criminal citation which you ignored which resulted in a fine, that would remain. The statute of limitations does not apply. The problem that is with criminal fines, the states are all part of a driver's license compact and if the fine is unpaid then a block is placed on your license and you cannot renew until you get this taken care of.
The fact that you called the sheriff and were advised to ignore is not relevant and does not mean that you do not owe the debt/fine. First, the sheriff should not be giving legal advice. More importantly, any fines are owed to the county - the sheriff's office may take a cut, but any fines are paid to the county and the sheriff's office has no right to waive any fines. It may also be the county trying to collect and the collector represents the county, not the sheriff.
However, your post is somewhat puzzling though since you deny you were given a citation and you do not complain about any blocks on your driver's license.
I think maybe to save yourself some attorney fees, write a letter to the collection agency via certified mail return receipt requested so you can prove that you sent it and that they got it. Indicate that you deny liability for the debt because: (1) you received no citation and this resulted in no fine; (2) you believe that collection is barred by the statute of limitations; (3) and if they insist otherwise, to provide you with validation of the debt. Demand that they also provide you with a citation or reference to authority which provides that the FDCPA does not apply. Also state in the letter that the collector is not to call you at work and that any further communication is to be in writing and directed to your home address. See what, if anything, gets sent back.
If this is not for a fine but is a civil debt and its not affecting you in any way, then you probably can ignore it. If this is for a fine, then maybe you should consult a traffic attorney in Georgia (I am Georgia-licensed but I don't handle traffic offenses). You should not need more than a 30-60 minute consult. You just want advice - you don't need any representation.
If you do owe, see if you can settle for less. If the creditor agrees, get a letter before you send any money advising as to how much is owed and what the settlement amount is for, to whom you make payment, by what date and where. Make sure the letter also indicates that if you pay the settlement amount no further monies will be owed . Pay by a money order and make a copy of it. keep it and the settlement letter forever. 30 days after your funds are sent, follow-up and get a letter acknowledging receipt of your funds and that no further monies are owed.