Q. I lost my job and was unable to make my credit card payments. The debt was charged off and sold to collection agencies. The latest collection agency now says because of interest and fees, the debt has gone from $500 when it was charged off by Capital One to more than $1,000. Can they continue to charge interest and fees after a charge-off and the debt being sold to a collection agency?

A. No. The Federal Trade Commission says a collection agency cannot charge fees and interest on your debt. They can only collect the amount that was charged off: in your case, $500.

To file a complaint against the collection agency, you can call the FTC at 1-877-382-4357 from 9 a.m. until 8 p.m. Monday through Friday, Eastern Time.

Also, take a look at our 10-step plan to get debt collectors off your back. It explains how they work and how to negotiate with them.

Our report on 10 things debt collectors can't do explains the rules they must follow from the federal Fair Debt Collection Practices Act.