My internet connection was terribly unstable yesterday evening and totally gone this morning.
But the problem seems to be more or less fixed now and the trobulemaker has been identified and countermeasures have been taken against further sabotage from the same source.
In translation, my landlady got visitors yesterday, her son and his wife and their 1 year old kid. Said kid had been playing with the antenna of the router. One of them was compleetely loose and is now taped to the router with ducttape (by me) and the other one is now more or less fastened as intended and I am praying to whatever is holy that the router will keep on working. It has also been moved to a more secure location, but you probably know how those small kids are, if they want to get to something, they will get to it.