Some audio files won't delete or play on my alcatel phone

I copied audio files (music) from my desktop computer to my alcatel. I only have internal storage, It seems the ones I copied on a specific day won't play. Message is "We cannot play this file" They also cannot be moved to trash. The message I get is " Couldn't move file to bin. Something is wrong with the file" Now these files do not appear in the music app of my phone. They only appear in the audio section of the files app. If I go to files, I can see at the top folders all/downloads/ and then one with one with an odd sequence of stuff eg it starts off with a rectangle, then ?5x and so on. This is where all these files are stored. I can't rename them either. Note. As I stil have the files on my computer. I tried copying one of them to the phone, and it plays fine. So basically, the files I am having problems with are in the audio section of files. But the music app does not recognise them. They are in a folder with an odd name, and I can't delete them. I would like to be able to delete them.