I'm on web and this was on endless, I kept the package overnightn in the shed for just one night, whit no stamps on it.
I must have weighed the package when I got it initially, but I don't remember the value, when I wheighed it for shipping the day after, it actually showed 0 grams, and yes I made sure it was on the scale, not next to it, not behind it but perfectly on the scale. I also put it back in the shed and then took it back out to make sure, without any change.
Since it was less than 10 grams, I put a 50 cent stamp on it and send it on it's way.
That's it, I wish KAN-Post good luck in fixing this issue