Here is a quick video of what you should see:
https://cloudup.com/cEI93qUXGle
If you do not see the Deactivate button, could you post a screenshot of your Jetpack menu so I can take a closer look?
because the button never loads
I'd be happy to look into that too. Could you post your site URL here, so I can have a look?
If you want it to remain private, you can also contact us via this contact form:
http://jetpack.me/contact-support/