There is a case opened by a buyer which I have appealed. This is the message on my account

[karlene75]

"eBay Customer Service has placed the appeal on hold until 23 Sep 2024 to allow time to provide additional documentation. If we need additional information, we'll send you a request by email."
I have additional information I'd like to provide. How can I email it to ebay?

[twyngwyn]

you should be able to respond to the case at will....

[repentatleisure1952]

 If we need additional information, we'll send you a request by email."

Seems self explanatory to me.

What type of case has the buyer opened?

It is my understanding that appeals apply after a case is closed.