I'm on xbox. My points are not updating either. This is a way to get points using the arc app on PC. The only other way is to submit a ticket and hope they get to you within a timely manner. There are lots of threads about people missing their arc points. The "missing points" is not a new problem.
I had the same problem with points not updating until someone said they were "making points via the arc app". the arc app is PC based. It gives points in 600 xp increments. Once a day you are able to cancel a single "mission" and get a new one if you choose. It gives you 3 "missions" such as "play neverwinter on 7…
The server is down currently, so I think they know the problem and are currently working on it. With a message stating "We are aware of login issues and we are working with Microsoft to resolve the issue."