Why is ebay so hard to reach? I’ve now received an email saying that my VAT ID is incorrect. That statement is not correct! But I can’t reply to this email, request a call, or anything else.... Does anyone have any idea what I can do?

You could check the legal notice, where you can find contact options. And it doesn’t necessarily have to be due to your VAT ID; it could also be because of the data not matching the data at the BZSt 100%.