Had a mic issue, recorded audio sounds horrible – like recorded in a cave

Hi, 

So, I had an unexpected mic issue when filming – and combined with the large, empty room we were in, I ended up with terrible audio. It sounds like we're filming in a large, empty cave. 

I've been playing around in Audition for hours but have not managed to make it sound any better. Anyone have any advice or ideas? Open to all suggestions. 

I've attached a clip so you can hear what I mean.