not as described, instead, an expensive giveaway

Instead of the described pillows, I received a simple inflatable cushion, quite small, with no removable cover and with an imprint of the website of an online store. So I have paid more than 5 euros for a freebie: /
Since this is not particularly worth the pillow at his own expense to return I asked the seller what he could offer to compensate me for. Here me a discount of 20% was at least been promised, I have also never received .... The damage stops at the price yes indeed limited, but is still outrageous.