Fairphone really has to sort out its warranty support

[Stefan]

The fastest way to a solved ticket is:

1. Create a ticket with all details about your problem.
2. Call Fairphone Support and tell them your ticket number.

Source:

Does calling right away slow down the support team? (Solution: Create a ticket first, then call!)

I would not recommend to call them by phone to contact them in the first attempt. Otherwise the average time of processing/solving (new and already existing) tickets will increase. What do you have to do when you must pick up the phone? Right: Interrupt your current work.