Q. I sent my credit card company a payment of $450 that was due on the 5th of the month. Then I sent a payment of $21,000 on the 12th to pay off my balance. But when I called today they said I still owed $182 in interest because my balance wasn't paid off as of the 5th. Can they charge me all that when my next payment wouldn't have been due until next month?

A. Yes. You are charged interest on your balance every day that it remains unpaid. When you don't pay the bill in full, your credit card even dispenses with the "grace period" for new purchases. Interest begins accruing the second you ring up the sale.

When you made your payment on the 5th, that $450 was deducted from your balance. But your credit card continued to charge interest on the remaining debt until you paid it off a week later. That just proves how quickly interest can add up and what a good move you made by paying it off.

Send your credit card issuer a final check for for the interest due and congratulate yourself on being out from under that huge debt. (Or at least transferring it to a lower-cost card.)