Colorado is a a one recorder state and so you can post it online. I just would not make ANY editorial comments about the recording whatsoever.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice.
A person who is party to a phone call can generally record it. If you are not a party to a phone call, you generally cannot. However, it's probably unwise to post such things. There are probably better ways to resolve the issue.