iCloud is sending meeting notifications on old invites

I installed iCloud a couple of weeks ago and it duplicated lots of entries which I deleted. Also it seemed to send lots of meeting notifications to lots of people that had previously invited me to meetings that have since passed. Obviously very embarrassing when sent to clients etc! I've since deleted iCloud from my mac, iPhone and iPad. People are still receiving notifications and my IP address has been banned from a particular domain because of alleged spamming (which I wouldn't know how to do!), I don't know if this is related.

Anybody have any ideas on what I should be doing different?

Cheers

Thanks for the link, worst thing is that in my panic to remove iCloud I lost all of my calendar entries......very frustrating!