could be any number of reasons.
Communication is usually the biggest one. If you can't use the guild chat a lot of people will kick you on principle because you can't follow directions.
Having a default name is also a good way to get kicked: Mol Elize, Mugami Chinzano, etc. We can't tell who you are, and you probably don't value communication/can't communicate is what that says.
Going early on heroic raids is a problem. Most guilds have a 24 hour no damage rule. Some even have an order: this person solos this raid, he gets next, etc.
Not participating in TB or following directions as to what to do will get you kicked.
With things as they are now, a lot of higher end guild have a minimum gp and require certain characters.
You getting kicked is almost certainly tied to one of the above.
