Everytime i try to login to icloud on my iphone it says "Cannot sign in: the maximum number of free accounts have been activated on this iphone." This is my first ios 5.0 device as I have just upgraded to 5.0.1 so I don't understand how I could have already used my free account.

I did purchase this iphone used, and it was previously on ios 5, but I downgraded it for the jailbreak.

How do I fix this problem?