I bought a song off an album and now I bought the whole album but I have two copies of the same song.

I bought a song and was meaning to complete the album but as soon as I got money the option to complete the album wasn't available and now I have two copies of the same song. What do I do? I mean obviously I should delete one of them but I feel it's a waste of the money I spent on the song originally. Is there anyway I can get my money back or did I learn a lesson to just download the album in one piece in the future?