Hello, going to give an update regarding my problem 😃
The Ziggo guy was here yesterday morning and changed the connector that is fixed in my wall (not sure about the name), after he did that everything worked fine for about 30 minutes. After 30 minutes the modem started to go "crazy" and restarted several times (all the lights in the modem flashed red). After some time (an hour I think) the internet got back and everything worked well for 24 hours.
The internet just crashed one time at 13:00 today (after 10 minutes it got back).
I'll attach the logs here just to be on the safe side, if anyone can look at then and see if everything is right I would appreciate.
But I think my problem is fixed now. At least the internet is way more stable 😃