Am I screwed here?

[savethesaveables]

I sold something on eBay. Unfortunately I had some ear issue / possible infection that made me dizzy at times, so I went to an urgent medical care center.

Anyway because of that I shipped late. Buyer opened a case. I didn't realize I entered one number of the tracking wrong and eBay gave me NO chance to state my side of the story. It just said to check back the case is unresolved or something. Well, the buyer already stated they received a refund even though the case was still open.. and then after a week or so they closed the case and my PayPal was negative balance. I went to buy something and the total was expensive.. that's when I noticed they're adding in the money from the charge back.

eBay sees a message from the buyer saying they still want the items, eBay sees the items were delivered because I had fixed the tracking number, but they tell me I have to create an invoice for the buyer in PayPal.

What if the buyer doesn't pay? I'm screwed?