Enhance audio recording

I missed an important meeting due to medical reasons and my colleague voice recorded the meeting so I can catchup and listen to the list of things that needs to get done. My manager was also leaving on vacation so I would not be able to connect with her. Only my colleague's voice is clear; the other party's voices are distorted, and you cannot understand what they are saying. I'm looking for someone skilled in audio manipulation to enhance the other party's voice.