My embarrassing bill-pay confession

A nasty upper respiratory virus recently laid me low. During this time I discovered, to my chagrin, how easy it is to overspend with a debit card when you're not feeling good.

I'm about to blame illness for yet another personal-finance gaffe: the Big Bill-Pay Snafu. 

It turned out to be correctable, but it was a boneheaded error. Here's hoping you will learn from my mistake. 

Pay early, pay often
A small credit card bill arrived over the weekend and I went online to pay it. I'd paid my other bills on Jan. 30. After typing in the amount, I happened to glance to the "last payment made" column on the right. It showed that this bill had already been paid, on Jan. 30. 

In fact, it had been overpaid -- by about $750.

• Bing: Should you use debit or credit?
  

I dug my check register -- yep, I'm a Luddite -- out of a drawer and quickly discerned the error. A few days earlier, I had typed the amount owed for credit card A into the payment box for credit card B.

What I'd done, basically, was give credit card B an interest-free $750 loan. And I still had to pay credit card A.

The Homer Simpson noise was invented for moments like this.

Can I have it back?
Normally my bills aren't very high, even though I charge everything I can in order to earn airline miles. (I'm donating them to my daughter and her fiancé for their honeymoon  trip.) This month, the bill for credit card A was a lot bigger than usual because of a recent trip to visit family and because of some car-related expenses, including getting the trunk latch repaired and buying a new battery.

Fortunately, my mistake was fixable. I called credit card B and asked if there was any way to get a refund on the overpayment. The agent couldn't have been nicer. She said this sort of thing happens fairly often and that after the payment cleared I could simply call back and request a refund. This was a pleasant surprise.

Of course, the refund will take 10 to 14 business days. This was not a surprise.

What I learned (and you can, too)
The most obvious lesson is to be very, very careful when paying bills online. Make sure your payees and amounts match up before authorizing payment. 

This snafu is another good argument for an emergency fund. Having that savings cushion meant I could move money into checking, pay the second card in full and avoid an interest charge. That's because I'm a Luddite and a deadbeat -- "deadbeat" being the credit industry's nickname for those who don't carry balances from month to month. 

Most of all, I've learned that illness and financial transactions don't get along. I've been paying bills online for almost four years and never had a problem.