Have have you ever, to your knowledge, dealt with Ace Cash services?
If you are If you are sure that that you can't possibly owe this money, you are probably right. What you need to do is to formally dispute the debt, because you have substantial consumer rights in this area under the Fair Debt Collection Practices Act. Here's a specific section of the FDCPA that you will find useful so that you can dispute any debt and/or send them a cease and desist letter:
§ 809. Validation of debts [15 USC 1692g]
(a) Within five days after the initial communication with a consumer in connection with the collection of any debt, a debt collector shall, unless the following information is contained in the initial communication or the consumer has paid the debt, send the consumer a written notice containing --
(1) the amount of the debt;
(2) the name of the creditor to whom the debt is owed;
(3) a statement that unless the consumer, within thirty days after receipt of the notice, disputes the validity of the debt, or any portion thereof, the debt will be assumed to be valid by the debt collector;
(4) a statement that if the consumer notifies the debt collector in writing within the thirty-day period that the debt, or any portion thereof, is disputed, the debt collector will obtain verification of the debt or a copy of a judgment against the consumer and a copy of such verification or judgment will be mailed to the consumer by the debt collector; and
(5) a statement that, upon the consumer's written request within the thirty-day period, the debt collector will provide the consumer with the name and address of the original creditor, if different from the current creditor.
(b) If the consumer notifies the debt collector in writing within the thirty-day period described in subsection (a) that the debt, or any portion thereof, is disputed, or that the consumer requests the name and address of the original creditor, the debt collector shall cease collection of the debt, or any disputed portion thereof, until the debt collector obtains verification of the debt or any copy of a judgment, or the name and address of the original creditor, and a copy of such verification or judgment, or name and address of the original creditor, is mailed to the consumer by the debt collector.
(c) The failure of a consumer to dispute the validity of a debt under this section may not be construed by any court as an admission of liability by the consumer.
The FTC gives a wonderful overview of the overaggressive and/or fake collection agencies and how to get them off of your back, where to report them, where to learn more, etc. And it's pretty straightforward.
But you want to dispute the debt -- that's the term you use with them, and you should do it in writing.
Once you have disputed the debt they have to leave you alone. If they don't, you can report every harassing message these folks make to the Federal Trade Commission and they can be fined $1,000 for each incident.
If these folks are out-and-out scammers, they may not be deterred by your invoking the name of the Federal Trade Commission, But they will also know that you know your rights and that you're not about to pay up if they can't prove you owe this debt.
If you really do owe this money and you've disputed the debt, they can sue you for the funds. But I doubt that will happen. Chances are high that this is just a scam, or they would be calling you rather than emailing.