Audio Files On My Android Phone?

[countrykid]

I'm looking to free up memory on my moto G5S.
Clicked on Storage which shows I have 4.3Gb used up in Music/Audio although as such I don't have music saved on my phone. I just log in to YouTube and play music that way in my YouTube library.
So I was puzzled what the 4.3Gb was taken up by.
Having gone in to it, it shows several apps including Alexa and BBC Sounds and 'Audio Files'
Looking closely at these audio files they correspond to CDs purchased from Amazon years ago which at the time offered a free MP3 download, which then I had no use for and didn't (knowingly)download
Clicking on these files shows that they are indeed MP3 files.

I cannot actually play these on my phone and I've no idea how they have been saved to my phone. It's not something I've actively done. Might it relate to having recently bought an Amazon echo dot, which can access those digital versions of those cds via Amazon music?

If I delete these MP3 files on the phone to free up memory, will they still be available in my Amazon account to play on the echo dot?. Thanks.

[derek-33]

go into apps and delete the cache in you tube alexa and bbc sounds then go into storage and settings and delete cache there you wont loose any files
thats what i do