Yep, I got this exact email from eBay and then a second one banning me permanently with no recourse for appeal.
I have no idea what I did except for connect my Shopify account with eBay - and when I called up I was told there was no ability to appeal the decision and they would not tell me what I did wrong.
So who knows!! I’m assuming this means I’m always banned from selling on eBay - that’s a lot of fun!!