You will have received an email - sometime between November 2015 and February 2016 in which there was the following statement
'We wish to inform you that the "Online Album free" service that you are currently using in MAGIX Online World will be discontinued in its current form from April 5, 2016.'
In the email there was information that you must backup / recover anything you uploaded to the Online Album before the 5th April.
If you did not so this and the Online album is now gone then there is no way to recover the uploaded images.