I have had this happen before and Brian fixed it but someone else is experiencing the issue today.
How to Reproduce:
Set quota to 5 songs (will probably work with 1 song also)
Upload 5 songs
Upload another should show error for quota issue
Delete all songs
Upload new song
Result - error stating you have maxed out your quota
It seems like the count is not being reset?
updated by @dazed: 06/30/20 05:46:52AM