I still did not receive any further information or what is going on about a complaint I made here over a week ago. I attache here the complaint again and hope to get some information soon about what can be further steps. Thank you in advance.  
Unfortunately I have to complain about my order (Reference: PLNJYNCEL).
I ordered fins and fin socks. I ordered 2 pairs of fin socks, which in my opinion is described online as 2 pairs, but I only received 2 single socks.
The worse thing is the quality of the fins. Unfortunately I was very disappointed. It is now the 3rd pair I have ordered from them of the same fins. So far I have always been very happy with them. They fit great. Always had size M (38-39) which have always been a bit tight but fit me well. Now I have ordered the same model again in the same size (38-39) but the elastic band around the foot is much looser. The material is much softer/stretchier than before. The fins now hardly give any support and no pressure can be built up when swimming (despite socks). This can't be the case if the same fins have always been rather small and very tight. At this price, I find such a big difference in quality and size unacceptable. Especially as I normally have size 40 shoes and wide feet. What has gone wrong? Unfortunately, I can't train or swim competitively with these fins.