eBay Sends All Your Information To Any Bidder Who Asks
At first I thought this was an accident or isolated incident but, as it turns out, this is actually eBay policy.
Typically the seller shouldn’t have anything to worry about, as we only allow members of eBay to request contact information. We allow any transaction partner (including a bidder) to request the buyer/seller’s contact information. This includes a phone number, and the address. This is for all members of the site, and something we’ve found be very helpful overall. There’s not a way to opt out of this as we expect it of everyone on the site, namely because we’re only a venue and don’t buy or sell the item directly.

