I believe eBay sells our names and phone numbers to "partner" companies.
I don't think you should ever believe an automated caller asking you to phone them back. If there was an urgent need for eBay to contact you, they would email or phone you. They wouldn't have a machine call you and say "hello sir and/or madame... bzzzt... your eBay and/or PayPal account is in grave danger... click click click... you must immediately call 1900SCAMYOU in order to reactive your account... beep click bzzt..."
Just ignore things like that. And the slightly better attempts as well. 😛