Account not found, and auto sync not turning off

First, I tried to post this, but your system would not allow me because it couldn't find my XMarks account for my email address, so I had to sign up for the first time. It is in the system, because I was able to change my password through the "I forgot my username or password" link. However, it still could not find the account when I then tried to post.

Now for the actual problem. XMarks synchronizes automatically even though I have the "Enable Automatic Synchronization" deselected, and always have. This causes slow systems with slow internet connections here in India to effectively hang up for 10 or more - sometimes many more - minutes when I start my browser about half the. How to I get automatic synchronization turned off?