Know what, unless you can back that claim up with some hard evidence I'll assume it's untrue.
I get your point, but I know multiple brands will honor a warranty from an used product from Amazon Warehouse. None I'm aware will honor a warranty from eBay (potential exception for manufacturer outlets, naturally)
No, you bought 2nd hand goods. In some exceptional circumstance Amazon MAY extend the return period but 30 days - same as ebay - is the contract. I believe all warranties for new goods are transferable to a second owner these days, but you would still need the original receipt to show when it was purchased "as new" and Amazon will not be supplying that. I happily buy loads of stuff from the Amazon warehouse and wouldn't flinch at buying a graphics car or any other component but you have to be aware of the facts. 30 days.
I believe you can still RMA through amazon, which is still better than eBay. Also some brands will allow warranty extended to 2nd hand users with a proper receipt like amazon's, but not ebay's
If a German seller wishes to make their goods available on Ebay UK they have to offer Paypal as payment method. So, unless you are signed into ebay.de or wherever to make your purchase you will have Paypal as an option. And if your Amazon warehouse item ceases to work on day 31?