Look just trying to get some help
This is good place to find advices and little of help.
But in your case there is probably nothing we can do.
My understanding is that you have already sent both pistols back to CZ... Is that right?
Frustration can be comprehensible, but nothing more can be done.
Nobody at this Forum can tell you why CZ haven't responded yet. Perhaps they are busy? Missed your message? Don't know how to answer your questions? -> We can only guess.
So once you sent your firearm... just be patient.