no power to thermostat, quick response greatly appreciated!

Hi all.

I took the thermostat apart to put up a new sheet of drywall, and then reassembled it. I took a video of it to make sure it went back together correctly.
Now there is no power to the thermostat.
No breakers flipped.

There are 9 slots in the thermostat, labeled: E AUX Y G O L R B C.
E and AUX had a black wire shunted across them. AUX had a white wire connected to it. Y had a yellow wire. O and L were empty. R had a red wire, B had a blue wire, and C had a copper wire connected to it.

I have 6 wires here, and not knowing what they all did, I tested all 30 possibilities with my tester and got no response.

I don't think I was rough with the wires in this process, but I did press them in a couple of times to get the thermostat case to close. It shouldn't have been enough to snap a wire of that thickness.

Now that I think about it, I did kind of swirl the wires together to push them through the wall. Something shorted out? Again, no breakers flipped.

What have I done wrong and what do I do now?

PS The urgency is that I have on A/C til I resolve this.
Thanks.