It was charging normally and now (last couple of months) it is charging slowly. If I use one particular cabe and jiggle it it (usually) charges normally, so I am guessing the USB C port is playing up and I will need to change the module. I can do that. Probably get a new battery at the same time. Is this covered under warranty? I brought it from BT 18/3/2021 so it is just under 2 years.
Why the world is making USB C standard is anyones guess.
As Yvmuell indicated, contact Fairphone support before you try a DIY as that may well void the warranty. As long as you contact Fairphone within the 2 years they are obliged to consider the warranty even if it takes them months to make a decision etc.
USB standard is to save having multiple chargers for example and the USB C port is very capable of fast charging and fast data transfer.
It seems you think there is something ‘wrong’ with it, as opposed to what a USB Micro ??
You will recieve a ticketnumber when your mail is arrived at support.
Support can be slow, but that doesn’t matter for the warranty.
The date of your mail in combination with the ticketnumber is leading for the claim for warranty.