New laptop, all looks OK except I keep getting told my accounts are not linked. When I try to sign into ebay from the link in Profile nothing happens. Profile says I AM linked but I got an email from myibidder saying I'm not, WTF. And yes, I tried unlinking/relinking with no result.

Not sure what you mean. You said you are linked, but then you are saying you are not.
Please provide the username you are getting the "not linked" emails for so I could check what's wrong.