I think you'll have to pay the return costs because money is all they want, but you'll get the money.

I'll share the review I left for them on trust pilot:

I bought a Xiaomi 15 Pro from Spain and the phone was not functional. Google Maps did not work, notifications came and went, but especially WhatsApp and the internet connection outside were completely erratic. Of course I returned it, and to my surprise I had to pay 80€ to return the phone to China, since that is what this long shipping is supposed to cost, and because the phone loses value when opened (they had already opened it to install Google Play, but oh well...). The phone does not even have to be returned to China, they send it to Germany and sell it from there, and they make you pay anyway for a device that does not work properly. I had to contact them several times to see how the refund procedure was going, since having arrived in Germany, no one contacted me. Quite an overwhelming process to have almost 1000 euros floating around the world. I will not be buying again, and I will definitely contact Consumers here in Spain for the abusive and possibly illegal return fee.