Exotic matter can be sent from person to person but when I received one it didn't give me anything it just disappeared.

You are correct- there is an issue with sending "special" materials through trade. I hope to fix this tonight. When this is done I can credit you the amount that was originally sent.

Ok, this has been fixed. You should see the exotic matter in your Trade -> Special tab now.

Cool got it! Thanks, what is exotic matter for anyway? Just quests?

Most commonly they are used for higher rank missions.