Firstly: Do you use any Ad- or Script-Blockers in your browser (NoScript, Ghostery, AdBlock …)? They could cause unexpected behaviour on some websites, for instance if necessary scripts cannot be loaded/executed or certain browser operations are blocked. I realized that one of these prevents me from logging into my 12return account, so I disabled them for this particular page.
Secondly: Fairphone is barely to blaim for a system they rent from a service provider, namely 12return. I don’t know to what extent Fairphone can customize that software, but if the system itself has an error, it’s most likely the maintainer 12return who is to blaim.
Thirdly: It is absolutely reasonable for the support to suggest seemingly dull or stupid “first aid” actions. If you had worked in IT support (which I did professionally for a short time and am still doing on a hobby basis), you would know how utterly stupid some “problems” actually are and how many unnecessary tickets are created by issues which you can solve by absolutely simple actions (e.g. “unplug your whatever” or “reboot your device”).
Finally: If you consider 520€ a “premium price” and expect premium hardware and services, you obviously didn’t understand what Fairphone is about. Take a look at the cost breakdown of the Fairphone 2 to learn where the money goes.
For instance: Just because a certain degree of the phone’s price is invested for “green” projects and to reduce the exploitation of people, doesn’t make the product or it’s producer automatically better in technical terms or in terms of provided services.
And by the way:
Since you seem to read my “murphy’s law” statement as the explanation for everything, let me clearify:
It is NOT an explanation. Saying “anything that can go wrong, will go wrong” simply means that in the end, there will always be that hand full of incidents, where - for whatever reason - the worst will happen (not saying that you are one of these). Even though, you might not be the only one having a bad time, I doubt that your case is any close to being common or usual.