If it is true that someone else is controlling your Nest, the way to get rid of them would probably be to log ALL users and devices out of your account, and then log back in and change your password.
However, it's more likely that the problem is internal to your own Nest. The place to start is by looking at whatever schedule may be in your Nest, even though you didn't set up a schedule yourself. I suggested this in my replies two weeks ago, and you said that you've tried all suggestions, but you didn't report back on what you saw when you looked at your Nest's schedule.
(Nobody is "running and hiding" -- not yet, anyway -- just hoping for more specifics from you. For example, @Markjosephp asked which model you have; without knowing that, nobody can provide specific instructions for anything because the models are so different.)
If I were having the problem you report, I would go into Settings and build a schedule that approximates the times and temperatures that I think I'll probably want. You can always override those temperatures manually, so it would be reasonably similar to the way you're using the Nest now. Then, if there is still this crazy behavior, I'd know that there was something really wrong and I'd probably try a factory reset before giving up completely. However, I am not any kind of expert; just a fellow Nest owner.
