When did you pay for the update service? which lasts for 12 months
It might be worth logging into your Magix account, going to My products and checking the details there. If that confirms your service is still current then you need to email infoservice@magix.net as soon as possible and ask for their help to correct this.
Welcome to the Magix user to user forums, so not a contact for any Magix staff, sorry. Hence, no-one who visits or posts here can confirm you have paid. Also, please do not post confidential data, like your order number to a public forum, like this one.
However if you go to https://www.magix.com/us/support/my-service-center/, log in, go to My Products and check the details for your installation of XDP, which will include the date your current Update Service expires. Should the additional time you have purchased not be listed, please email infoservice@magix.net and ask for their help.
Not sure if this is the same situation as yours. I had a problem trying to update to v19. Went through the process of updating but program stuck at v18. Fixed as follows:
Go to My_Products in Jeff's link above and install from there - it works and doesn't appear to loose any data (file/open recent still shows my latest files). Also My_Products has the key required to copy/paste to register