I can’t imagine a brand new seller selling anything without knowing anything about selling, let alone a massive amount of money like that

Especially with a high priced item going overseas, that is one sure way to be scammed by a buyer

If you fail to ship within your handling time, that will result in defects and possibly closure or your account by ebay

Chat is useless, they are not responsible for any of this and since you do not seem to be signed up to Managed Payments and verified to sell, there is literally nothing they can do

Managed Funds have been the only way for a buyer to be paid for over 6 years now

You really need to end any unsold items until you know how selling works