Rockstar Social Club Accounts Hacked

Rockstar have posted to their support page about how some usernames and passwords have been obtained from outside sources.

We are aware that unauthorized attempts have been made to access Rockstar Games Social Club accounts using email and password combinations sourced from unaffiliated, compromised websites or databases elsewhere on the internet. For the accounts affected, we are in the process of reverting those accounts back to their original owners. As a result, the ability to change email addresses for Social Club accounts has been temporarily disabled. See the following Rockstar Support article for more information here. As a reminder, it is a good policy to ensure that the Rockstar Games Social Club account username and password is not shared across multiple websites on the internet. For accounts affected with this issue, we are working to respond to customers to reinstate full user access within 24 hours of contacting Customer Support. Please continue to look to the Rockstar Support website for more information as it develops.

So for now you can't change your email address, and if you've having account issues get in touch with Rockstar support. And change your passwords!