The defect was due to you not sorting out the problem.
It is never sensible to get ebay involved, as once a case has been open, it is up to you to sort out. There is no means to escalate to ebay for a seller, but buyer can escalate if you have not refunded within 3 days.
As soon as ebay get involved they just refund, and give you a defect.
One defect should not do much harm, but I think as with private sellers, if the defect rate goes over 2%, then seller falls below standard and can face restrictions.