Bought music but not showing in music?!?

I have bought albums and music in the past e.g Ahmad by Ahmad.. when I give to iTunes it shows that it has been purchased but I can’t download it and it is not showing in my music. I have other music I have bought in the past which are not registered as bought so I have to buy them again e.g La belle et la bad boy by MC Solaar. I recently had to buy Heard it all before by Sunshine Anderson as I needed to use it for something when I had bought it before previously.. worried I’ve lost songs and albums.. Any idea why this is happening? Thanks