Your a killer ya know?

Can't you find Terrakion on a cave?

Ya but I killed him on accident

If you didn’t save your game after you defeated them then the only way to get them is through the GTS. If you didn’t save after defeating them then you can close it your game and reopen it, it should take you to your last save point and you can retry.

I saved

I can’t help you then

G zapdos can be found from Rolling Fields to East lake Axewell, terrakion can be found in lakeside cave

He knows were it is found. He just fainted them and can’t get them now

Then idk

They both respawn in their designated area. G Zapdos is in the wild area and idk where terrakion is but i know he respawns in the same place because cobalion does