Incorrect filenames lead to incorrect titles

Hi, newbie here. I'm cleaning up a 3 CD album with 36 tracks by Creedence Clearwater Revival. The files have incorrect titles and filenames. I can load the files and generate the correct metadata, but when I save it nothing happens with the original files. I've spent two days trying to get this to work and consulted the documentation and googled for answers, but I'm stumped. I suspect the tagging format of my files is not what it should be, but I'm unable to figure out what it is (nothing in the details of the metadata of the files).

What kind of files are these?
Where do you expect to see metadata?
Could you supply a screendump of MP3tag and a selected file?

Perhaps one thing in advance: the metadata field TITLE is not the same as the filename. So, editing the title does not update the filename. MP3tag has functions to do so, though.

Thanks for your reply. These are m4a files. I may be attempting something MP3Tag is not capable of doing.

I am trying to use Discogs or MusicBrainz as tag sources to change the titles so they are correctly matched with the corresponding song. Right now, they are all mixed up. I get to the screen where the existing tracks are shown on the left with the more complete metadata on the right.

But the titles in almost every file are not correct. They are in the correct order on the right, but the length of the song (and the song) are not correct for those titles.

I'm not seeing a way to attach screenshots, sorry. I can if you point me to the icon for doing that.

Thanks for your help.

see here:

If you do not see the correct versions of files then you have to investigate which release is the right one. MP3tag has no influence on the quality of the supplied data, it merely shows it.