Update 03/07/2017: https is starting to appear on webmail but http still seems to work in places and until it is removed and cookies are secure, it is probably best to avoid using Ebay.
Ebay mocks Data Protection laws by sending emails over http. When its site states its email service is secure.
This is already illegal under Data Protection laws. It doesn’t even need upcoming GDPR: the way eBay describes their security means they are misleading users and even without GDPR, this kind of messaging system should be governed under laws like PECR.