Re: Mass Effect 3 In-game Purchases Undergoing Maintenance Error
Try to clear your EA app cache.
If that don't works only support can help in such a case.
Restarting the router, changing the region to English (if not already set this way), changing Browsers, disabling add-ons especially anti-script and ad-block software could help with the contact attempt.
The link to EA's Support is here.
1. In "Search game or Topic" Search for "EA app".
2. Click on "See all Help Topics"
3. Click "I need help logging in to my EA Account"
4. Choose a contact option, preferable "Chat with us"
(EA help Guide.)
You also could try EAs Support on Twitter or on Facebook.