So the punching bag ordered, delivery was as usual the next day, the lower chamber is filled with water and off we went. My son has it but always managed to beat so strong that the bag has been set aside and is not risen again. Anons is the part actually quite durable. I thought until yesterday. Then I discovered a damp patch on the carpet and guessed wrong. In fact: a small tear at the seam could be seen, from which it bubbled merrily to himself. So ... get the hell out of that thing out of the apartment.
A call to Amazon and I got enough of post replacement, although the four-week return period had already expired. Exemplary customer service - thank you very much !!! We have to stand now filled not with water but dry sand. Although this has lasted a good hour, but gives much better stability and we now have no more fear of a possible further flooding. Let's see how long that part of this time by holding ;-)