How about the accessories:
Five sizes of ear pads ?
6.3 mm (1/4”) adapter ?
2 m (78-3/4”) extension cable ?
Soft carrying case ?
Are there all of them included?
There are only two possibilities here:
1) Aliexpress likes to lose a good deal of money on EPH-100 transactions.
2) You received a counterfeit at the price of 28 euros (VERY likely).
You know the old saying, "when it looks too good to be true, it is".
Typical margin on audio hardware for resellers is 40-50 points, sometimes more if a unit has been put on discontinued clearance, or if the reseller buys in bulk. But not MUCH more, sometimes the only concession to the reseller is free freight. Additional discounts can occur for things like B-stock (slight cosmetic blemish etc), or even opened/returned/refurbished stock that still carries a warranty.
In the U.S. these 'phones retail for $199, but can be found for a street price of more like $130 or so. Even if a reseller were just looking to get rid of their stock of EPH-100 (not sure why they would when it is a very popular model), you'd still be paying someplace in the neighborhood of $100.
I'm not sure what the equivalent official retail, or "street" prices would be in Europe, but I am sure it can't be 28 euros for the genuine article.