Remove account without affecting the data I have a phone with a Google account from an external provider (namely gazeta.pl). At one moment, due to policy reasons, the mail provider changed the platform from Google to proprietary system. So it's no longer a Google account.

I have all the contacts connected to this old account. The same situation with all the apps in the store. I can't log to it anymore via Google means. I have another regular gmail connected as well, I can install new apps, but cannot update anything (especially Google play services).

I need to have access to Play Store and update system. My best call is to remove the old account, but this will lead to losing all the contacts (SMS as well? I'm not sure). How to proceed without manually rewriting contacts? I would like to have them connected to my new gmail.
The way I see it, the only problem you have is losing your contacts if you sign out of your Google Account.

First of all, your contacts on your Google Account can be accessed on 
Google Contacts, so signing out of your Google Account on your phone doesn't necessarily mean losing all of your contacts on that account.

Secondly, transferring contacts from one Gmail account to another is fairly easy, and you can find a step by step guide on how to do so Here