iPhone Audio files

So I have an external audio app called audio stretch. And to use it you have to go online and download the audio files from there, and for months I did this, and a few months ago using the same downloads and everything I always have used, all it will do is save the audio file as a text document. Which is completely unusable. Can someone tell me how to fix this, because I’ve been stuck on this for months. I have pictures. Second picture is a song that worked before this happened. And the first picture is what is happening making it completely unusable.