I got a new iPhone because I lost mine. After logging into Game Center it will let me continue where I left of on all my games accept Game of Thrones Conquest. In settings on that game it says I can switch accounts but when I hit Game Center it says I’m already logged in. This new account has overridden my other account on the same Game Center. I need help. A lot of money wasted if I can’t recovery the previous game save data.
iPhone XS Max, iOS 13
This might be your problem. See What to do when the Mac App Store shows a different Apple ID for software updates https://www.macworld.com/article/3267709/mac-app-store-apple-id.html. This document refers to a prior owner, but is also applies to cases where a current owner's old Apple ID is the problem.
Basically, If an app is purchased/downloaded using one Apple ID, then you can't update it with with another Apple ID. The app is inextricably linked to the first Apple ID. You'll have to delete it and repurchase/download it again with the second Apple ID unless you use family sharing (see below).
As an alternative to deletion, you can set up family sharing between the IDs to share purchases made with them. See:
Family Sharing https://support.apple.com/en-us/HT201060
Set up Family Sharing https://support.apple.com/en-us/HT201088
Can’t recover Game of Thrones Conquest
