trying to sync old battle log acc

Since this is an account issue you will need to speak with an EA Game Advisor. Be advised that you will be asked the security questions that you set up when creating your account before any changes are made to your account. You can find a game advisor here:

1 Click on the following link: https://help.ea.com/contact-us
2 Make sure you are logged in (top right corner)
3 Click on the blue button "Contact a Game Advisor"
4 Enter the name of your game or product (or "Origin" for account-related issues) and click "Find Solutions"
5 Select the type of issue and the platform you play on, and click on "Find Solutions".
6 Click on the blue button "I still need help" if the FAQ articles do not apply to your situation.
7 Select a contact option. Note that you may get different contact options depending on your country.

I recommend that you use the telephone option and the “call me” option so you don't have to stay on hold for a long time

Did you receive that message from the live chat? If so try the telephone and the "call me" option which is available to North America and most of Europe to speak with a live person who can make the changes while they speak with you.