I dont have the phone. Its my old phone but I am still logged onto my mail. How can I deactivate it from my actual phone? I dont have the old phone on me.
Assuming that you want to stop your Google account from syncing to your phone.
To stop Google from syncing to your device, you should sign out of your account. To do that remotely, go to this page, sign into the same account as the one on your old phone, scroll down to the bottom of the page, press on the name of the device, and press remove. This will remove your account from your old phone and will stop any new info from coming in. You'll have to sign back in, in order to resume sync.
If you want to fully erase everything that's on the phone, go to Android.com/find log into your account, and press erase in the pop-up press erase again. As long as your phone is on and has internet connection, everything that's on it will be deleted.