Come to think of it... in the past I've spoken with a German who did pyro and he said customs in Germany are not a joke.
If you get cought buying chemicals etc. for fireworks making, you're in big trouble.
I assume the Czechs are aware of that and therefor don't ship to Germany.
Thanks everyone for your input so far, it reflects more how this company is / handles orders.
I'm still considering buying timefuse from them

I honestly haven't found a cheaper source.