Hi Xenia
At the moment there are a load more tickets than usual for lost kitties and other issues, (mostly due to LL) so that they are taking longer to get answered than usual. Mine took 6 hours the other day but usually it's within a few hours or minutes even.
Kitten Longmeadow takes care of most of the tickets and i believe she is on Pacific time, therefore SL time.
If you click on "pedigree" at the top of the page you will see that your kitties are in fact all there so they never get lost, even if you delete them by mistake, so no need to hang onto "proof". The only way for them to disappear is if you click the "menagerie" button but even then they can still be retrieved.
So don't worry, as everyone can tell you, KittyCatS support is one of the very best that you'll ever find in SL.