recently purchesed music maker premium, while messing around with it i screwed some stuff up and ended up redownloading,now i am missing instruments and features i had purchesed from the store and cannot redownload as it says I already own it.how can i fix this?
Anything purchased from the store can be redownloaded without problem, unless there is some part of a previous install, which has not been successfully removed and hence, MM (and the Store) thinks it is still available to use on your computer!
Because of the "messing around" you did (!!) you need, first, to completely uninstall everything to do with MM. Please follow exactly the procedure in this tutorial. Although written to assist with Win 10 Upgrade problems it is also applicable to circumstances like yours where a previous uninstall and attempted reinstall has failed.
Once that process has been successfully completed, reboot your computer, reinstall MM, be prepared to activate/register it with your previous serial number. Once this has been successfully done you should then be able to redownload and install ALL your previously-purchased instruments, soundpools, effects, etc.