What Will Happen?

Awhile ago I posted something to sell on ebay. I've only sold one
thing on ebay a few years ago, which was a successful transaction. In
the meantime, I've bought quite a few things all with no problem.

THe other day I posted something and I posted it incorrectly without a
reserve. I didn't realize the item closed for a ridiculously low
amount, so basically I was making $1 on the item. The total amount
was $12.

Immediately upon my receipt of the ebay email notifying me that the
item had been sold, I emailed the buyer and explained my problem (in a
very nice way I might add) and hoped they would understand if I didn't
want to sell the item. I received no response and thought perhaps
everything was fine.

Two weeks later I received an email from paypal saying the buyer had
paid for the item. So I emailed the buyer again explaining the issue
I was having and I immediately, that same day, refunded their money.

Today I received a nasty email stating they were going to report me to
ebay. It's unbelievable to me that someone would do this over a small

Does anyone know what the ramifications of this will be to me?