Weird. This is a new one on me, spud01, and I'm hard pressed to explain it without being able to see the account.
I assume you've checked will all others who have access to the account, to make sure they are not taking matters into their own hands? I've known clients to make changes in accounts that are managed by others, but to which they have access...
I'm glad you've contacted AdWords support, as they can take a look into the account itself, the history of changes, etc.
I trust your query will be answered soon, and I'd be interested to know the outcome.