Sorry to hear you be that unlucky to receive a broken phone out of the box.
About support, expect 2+ months reply time.
i expect you request will be treated as high priority.
low priority requests will mostly answered after about 3 months.
Have you received the automatic anser from Fairphone? in that email you can find a link to the website, here you can follow your seport ticket.
When you can’t wait and it’s not possible to visit one of the Fairphone Angels like suggested by @urs_lesse.
A different option i can think of is putting your phone carefully back it the box and buy a other Fairphone 5 from a trusted reseller so you can use that one and wait for Fairphone to take the broken phone back and send back your money.
Most resellers wil have shops how can help you directly if you have a issue with your phone.
After all i think its best to be patient and wait for Fairphone to answer your email.
which you good luck.
Tom