Most sites prevent this incl Youtube. Reason being that there should be a connection between the audio or video that was presented and the feedback it has received. Both qualitative feedback (what people say) and in quantity (how many interacted). This may more be a problem on large sites like youtube where a poster could keep on replacing videos accumulating millions of views and comments. It is surely actively used on Amazon where sellers first post a quality product getting good rating and then posting some cheap copy garbage on same item. I personally think it is best to maintain that you can change description, lyrics, properties, even artwork would be OK. But the main product, the song, cannot be replaced. If you post a new mix of your latest, I promise to listen and comment ;-)

You are a rock, Kenneth :) when I see it your way it makes sense. But you need to do all the settings again when you only want to correct a mistake I have change the mix a bit an make it a bit wider too so I will upload a new version :)

I had this kind of issue some times ago, this is why I always listen entirely a new piece I just uploaded and if you feel there is something wrong, as no one has listened yet, it's the right moment to delete the song and upload a new one (after having saved the description of course).

Kenneth said it exactly right. There are a number of things you can edit, but the audio itself is not one of them. That would leave things too open for shenanigans.

I don't know about opening it up for shenanigans, but a good idea would be to have 'Versions' which attach to the original, so when the collaboration has finished, you edit the song, you can choose to upload a new version which attaches to the original version, then if you want, the original version can be deleted, and the restrictions can still apply to uploading new versions as it does for uploading a new song for free accounts. The way I see this site, it's not really a collaboration site, but (primarily) a site where people can upload their songs and get reviews, unlike other collaboration sites I've come across that have provisions to upload seps/stems, mixes and lyrics as well as uploading new versions of the mixes, then the ability to 'close' out the collaboration which would stop any more additions, then that mix can either be shared on other platforms such as 'Soundcloud' and/or posted here for feedback. It's not as simple as upload seps and let others mess around with them, on one collaborations site, I noticed the projects can either be 'Public', for any member to collaborate on, 'Restricted' means the project can only collaborated on when a request from another member is sent, or 'Private' for invites only, and not visible to anyone.