DHgate.com complaint: Awful customer service

I ordered EU size 42 trainers and received EU size 38 trainers, I immediately got in touch with the seller who told me to send pictures which I did, you could see that the trainers they sent were to small and the wrong size, they did not offer anything to me so I opened a mediation which DHgate to get involved, they also wanted pictures and so I sent them which again you could see they were the wrong size, the said there’s 2 options 1. Keep the trainers and receive a $20 partial refund or 2. Return the shoes and the seller reimburse’s the money paid for postage when they receive them back, I opted for option 2 as I never had any use for trainers that are too small for my feet and wanted my money back, DHgate persistently told me to take option 1 which I didn’t want and I persistently told them I wanted to return the trainers, eventually they ended up saying I couldn’t return the trainers and issued me a partial refund of $20, all I wanted to do is return the trainers and they wouldn’t let me and now I am stuck with trainers that are too small and £62 out of pocket, in my opinion they’re customer service is really bad! The photo I have attached is my size EU 42 on the left and what they sent me on the right EU 38.