Ripped off by roofer - can I get money back

baloooo2

In short, had water coming through bathroom ceiling. I told roofer I thought it was coming in through the extractor vent. He ignored me, went up on roof, said roof needed painting with some kind of special stuff, painted bits of it, charged me £500 and left.
A few weeks later, water still leaking through extractor vent. The guy came back and looked around, said "Oh, it's leaking through your extractor vent. You need a replacement for the old asbestos cap. I'll get a quote and get back to you." More than a week later I haven't heard from him, so get another guy round and he says "You don't have any cap on your extractor vent (I think this is true - I can see it from the window), I can get you one and fit it for £90". So I've told him to go ahead and do it.
I'm really angry with the first guy who charged me £500 for doing something which clearly didn't need to be done and not actually fixing the problem. Is there any way I can get the money back, or at least part of it? I found him on Checkatrade of all places, so I will be sending really bad feedback but I'm shocked such a cowboy could be on there.