Have you registered and activated the version of Music Maker which you have? Which is it, by the way? Did you have any older versions of MM installed previously? Have you checked to ensure those versions are listed in your current installation as activated?
If you have done all the above, have you checked whether anything is showing for you under the Downloads tab? That is where previously-purchased and still-available soundpools, instruments etc., will be listed.
I have 2020 installed. I did have them under the download tabs a while ago and it said to finish install I would need to authorise installation rights. As I couldn't figure this out I uninstalled the items, but now when I look for them in the store they show as activated but does not give me the option to download and it does not show up in my owned loops section. Thanks for the help btw guys, hopefully we can sort this.