Signing android APK production?

Hi.

I uploaded my first game on Google Play a few days ago,
this was done without signing the APK, as in no changes were made in ‘publish’ in the player settings. It uploaded without any issues to production.

Today I have added Google Play Services which required me to make a keystore and sign it using that. When I try to upload the APK to Google Play it tells me that it’s invalid and that I should be using the one previously used. However, that was the unsigned one. Now when switching back to unsigned it won’t accept the APK because it is in debug mode.

Note: I am using a different computer than the one that was used to build the previous version that was uploaded to the Play Store.

Is there any way for me to still upload an update to the game, or am I forced to create a new one? I really hope that there’s a way to update it, otherwise I would lose the few users I have.

Thank you.

You should ask google about the problem. It seems to be on their side, not unity’s. Tell them you forgot to sign the application in the beginning and maybe they can do something about it.