Is it a really bad thing to have an unpaid item strike against you on ebay?

my daughter won an item on my facebook after i had told her not to bid on it. i explained things to the seller in china. the reply was its ok . dont worry about it. im still getting bills. ive sent two more emails to the seller. im giving up now. let ebay do its worst. but is it so bad. my account is immaculate up to now with 100% feedback.