Question: The leader of our clan left the clan and went to another clan. He is an awesome lvl 118 player. I also left the clan and tried to join other clans, but everyone declined it l. Now my mail box is full with **"Clan Request Declined"**. So is there a way I can recover his mail to see which clan he went to?

The player's name is *Velkar* if that helps.

Answer: 
No, there's no way to get back old mail that got deleted. It's also not possible to search for a particular player (although it is an often requested feature...). If you didn't note the clan tag or clan name, and you aren't friends on social media (ie, Facebook or Game Center), then you aren't likely to find this player.
Join your old clan and look at the chat. Find the notification saying that he left the clan. Click the notification and click profile or view clan. Then bookmark the clan.