We had our mail stored in September, worked perfectly.
Arranged it all online, got a confirmation mail AND a confirmation letter a few days later.
They started delivering again exactly the date we had stated.
So absolutely no complaint from our part - except we got 2 catalogues that were not meant for us, but that does not bother us, rather the person they were meant for.
In order not to receive any junk I put a sign on the box saying "Keine Werbung einwerfen" - which seemed to work at first. Until some of our nerdy neigbours must have taken it of, cos my friend who I'd asked to check once a week said the sign was on the box when she first checked, but then it has been taken off.
In our house they don't seem to like handwritten pink signs glued on postboxes instead of properly printed metal signs...