yeah, i read about that requirement. there is a way to interrogate skype's windows desktop client install to extract the account creation date. even squirreled away a support link about how to do this which of course is now broken.
Were you worried at all about the culprit using the access to figure out other accounts? My account had a balance so I assume it had some old credit card info in it or something similar.
In messaging with support, they advised that the system would 'automatically' identify the account as compromised and eventually block it. This doesn't seem that likely so I will ping them again in a few hours.
Edit: new link here
https://answers.microsoft.com/en-us/skype/forum/all/skype-ac...