It really only works with the right bottle. Only the DUO bottles.
And otherwise you can exchange the device. A 2-year guarantee is common practice throughout Europe.

I have also had this problem, do you use the right bottle?

I too have produced a "flood" once when I pressed too long. Unfortunately, Sodastream does not give clear instructions and you cannot see what is happening in the bottle. Pressing two to three times at the most, for 2 seconds at the most, works.

It's actually quite easy, as the previous speaker wrote, press 3 times briefly, then there is enough carbon dioxide in there and there is no mess.
You can't really go wrong with either system.

You have to press down 3 times, not too long, and then open slowly, not too fast, then it should work.