Our guild was kicked out from guildwar in the middle of the week. We already had attackes and defense. 9 server, Legion
If you have not already please submit an in game support ticket and request the issue be looked into.
Did you happen to be tied with anyone at the beginning of the week?
Before GW starts his monday our guild also was out of ranking (last week we finished 2nd). Our guildmaster wrote a letter to support. If you ask about it