I've been plundered how can you locate them?

If your ESTATE has been attacked and plundered, then your Mail in the War category will tell you the coordinates where the scout and the attack came from. A wealthy, clever, and disciplined attacker can take countermeasures to hide himself with a three-step process: first teleport next to you, then scout you and attack you, and finally teleport elsewhere. If your CLOUDCHASER or BOUNTY has been plundered, maybe that's just the cost of doing business.