I'm missing a couple of things. First, the story has to be compelling to hook an agent (and readers). A mobile franchise tool dealer doesn't, in and of itself, provide this.
You wrote: Now, both the company that sold him a bill of goods and the customers that he must collect from, are twisting him into a psycological nightmare, that sets in motion a chain of events from which he can't escape.
So he and his customers have been screwed, how does this lead to "psycological nightmare" and "set in motion a chain of events from which he can't escape". There are steps missing that make this seem to defy logic. You need to provide a little more to show how one leads to the other.
This description is a start, but too short. It is perfectly alright to use more words. You get an entire page in a query letter. Use it. One short paragraph is a pleasant greeting for the agent and a description of your work.
Dear Ms Agent,
I am an avid reader of your blog and we met at the Toolmakers Writing conference. Please consider my novel, a 120,000 word psychological thriller entitled "Tooled to Kill" .
Then you creatively summerize your novel. This is followed by a short paragraph outlining your credentials (you probably don't have any so use this additional space for desribing your novel). Then close by thanking the agent and asking for representation, as well as offering any additional material she may need. MAKE SURE YOUR CONTACT INFO IS INCLUDED.
The other advice, is voice sells manuscripts these days. Make sure you have a strong voice in your manuscript, and make sure that same voice shows up in your query. Your query is also a writing sample for the agent.
Good luck -Craven