Songs from a purchased album are missing from music

I purchased an album a while back on itunes on my ipad. The complete album I purchased has 23 tracks total. I’ve noticed recently that I only have 8 of those tracks showing and playable in the music app. If I go into itunes it shows purchased next to the album and each of the 23 songs but no option to play the full song or redownload any that are missing. They are not in my purchased list of music or in downloads. When I go into the music app and try to add one of the missing songs to my library it prompts me to subscribe to apple music. Why can’t I redownload music that I purchased? Even though I have 8 of the tracks in music and itunes shows them all as purchased, itunes app will only play a demo of any song, even the ones i can play in full in music.