iTunes Match and associated apple ID

I have an issue with itunes match.

I just disconnected from itunes match to be able to change some songs information (it is impossible to do it when IM is on since it erases the changes every time..). When I tried to log back in IM it says that my computer is associated with a different apple ID and that I cannot change this for 90 days?????

What is that? I didn't associate my computer with a different IM id. How can that be? I will not be able to access my IM for 90 days????

Help please

Pascal