This got me worried for I too check my accounts online.
What I noticed is that the postpaid numbers could still be accessed BUT the prepaid numbers I enrolled are not there anymore.
I was still able to access my prepaid accounts enrolled in "My Account" but as of this morning they are nowhere to be found.
Hoping this is only temporary.
Is this for the GServices App? I experienced that before but seems it is ok now. Try to uninstall and re-install the app on your phone and register your accounts again.
I just checked mine earlier, it seems fine.