Just a suggestion: Have you tried to return it through Fairphone Support? Experience shows in such cases the company has often reimbursed buyers and still let them keep the unneeded case. Perhaps they might even send you a “free” FP4 case of your choice instead of a reimbursement.
Oh, and you might want to add the COLOUR to your description.
Thanks for your reply and kind advice !
I updated the title of the thread, it’s a green case
And I just called the Support Team. They can’t help me because I already ordered the FP4 Protective Case through another order. They actually advised me to come to the forum.