The Fairphone repair center (which is another company) does not micro-solder, like most repair centers/shops. Thus they could only change the whole mainboard, I guess. There are only very few repair shops doing such delicate work such as changing some components on the board (like the USB socket for example). I am not sure if anyone would change the headphone socket, but here you find a list of some shops that have been doing some micro soldering in the past; maybe one of them would be willing to change the headphone socket.
Parts like headphone or USB socket are prone to break and some of the weak points of mobile phones. For this reason they are not on the motherboard anymore on the FP2.
However, I am not even sure if Fairphone will get the mainboards back on stock again, as unfortunately they have been struggling to get spare parts for the FP1. You can read a bit about it here: How we are fixing the spare parts supply chain so you can repair your Fairphone - Fairphone
or follow discussions here:
FP1 Spare parts availability (batteries, displays, motherboards, etc. [out of stock!?])
If you cannot get it repaired, you can also check this thread, as sometimes people sell phones with broken displays etc., so you may find a working mainboard for a decent price:
https://forum.fairphone.com/t/unofficial-second-hand-fairphone-1-marketplace-sell-buy/6453?u=freibadschwimmer