Do I have to provide my email address & phone number to an unknown seller so that they can send me a paid for postage return label so I can return items to them? I've not returned items before so I don't know what the label actually requires. Thanks for your advice.
No, absolutely not. But why is he asking at all...? You should have opened a Return Request, so that Ebay can supply you with a tracked returns label. Read Ebay's Money Back Guarantee, and follow the instructions. It's on every listing and in various other places across the site. Or use the More Actions dropdown beside the transaction on your Purchase History page.
Have you opened an Ebay Returns Case? If not do it now you have 30 days to use the EBay Money Back Guarantee. EBay will send you the Label. You can Escalate the Case on day 9 - 21 for Ebay to Step in. They will force the Refund.
If you have opened a "not as described case" then simply do nothing. The seller should send you the label through the case. If he does not then on day 9 simply escalate the case and eBay will probably refund without return.
Even if this is not simply a "seller's excuse" they have got to understand the system and it it not your job [!!] to inform them.
If the seller really needs this information it is available to him as part of the selling process, but I see no reason why you should supply it, after all you are sending to him, not he to you.
