Where has all our music Gone?

Hi

We have a couple of Ipad Pros 17 inch that we use for work, Both are up to date and working perfectly......however.

On one we keep our music library. This is NOT purchased or downloaded music and sound files but original tracks composed for clients. We have not had reason to open this for a few months but were horrified to find when we did that the vast majority of our music is now missing or if it is listed has a Cloud symbol with an ! in it and the message "The song could not be used because the original file could not be found"

As all these files were kept on this computer and were NOT removed where can they be?

We have not always had enough cloud storage so have had to upgrade and upgrade our plan but the fact is that while the tracks are listed and in the correct place in the Itunes library they cannot be found since icloud etc.

Please can anyone advise where they are and how we get things back to as they were pre Icloud etc. We ahve plenty of space on our hard drives and dont need access on personal devices etc.

Many thanks and I hope someone out there in Macland can help.