[FFmpeg-user] Help with Broken Audio Download Please.

[Budge]

I have five GiP downloads of "Composer of the Week" from a couple of years
back which should have been .m4a files but are in my system as .mp3. 

Sadly they do not play and I am sure they are not .mp3 files.  These could
have been the result of one of my frequent errors but I would like
retrieve them if possible.

Running ffmpef on them gives me :-

Output file #0 does not contain any stream

Running ffprobe gives me:-

[aac @ 0x130e660] Error decoding AAC frame header.


Running file gives me:-

:~ file Composer_of_the_Week_-_Carl_Philipp_Emmanuel_Bach_1714-1788_1._The_Belligerent_Flautist.mp3

Composer_of_the_Week_-_Carl_Philipp_Emmanuel_Bach_1714-1788_1._The_Belligerent_Flautist.mp3:
Audio file with ID3 version 2.4.0

The files should be AAC audio files in .m4a container but I messed up the downloading. They are all about 97 MiB and the above suggests to me they should be recoverable if only I knew correct commands!!!

Could somebody please help me with this.
Budge