CANNOT SEND MESSAGES ON XBOX

I Play on the 360 and when trying to send messages through the global or local chat, you are limited to about 30 characters, cannot use any sort of question marks or periods or exclamations, and you cannot send more than 1 message every minute or so, or I get muted for over 5 minutes. Wtf is the deal? Im trying to ask questions for help online, and I cant even ask anybody anything because I keep getting f******* muted.