>>> Can I sue original guy for fraud?
You can't sue anyone for fraud because fraud is a criminal offence, whereas people are sued solely for civil debts.
You can't realistically launch a private (criminal) prosecution for fraud, simply because it would cost megabucks to do so. So any criminal prosecution would have to be initiated either publicly by the Crown Prosecution Service (acting on information provided by Trading Standards and/or the police) or privately by Trading Standards directly.
You can't sue a company for debt in the County Court unless they've failed to pay an amount which is due to you. So your first step would need to be to obtain the services of an 'expert' to calculate how much the company owes you. Then you'd need to send a formal written demand, stating the amount you were demanding, detailing the reasons for the demand and making it clear that failure to pay within a specified period would result in legal action. Then, when you failed to get your money, you could lodga a claim with the County Court.
So you need to contact both Trading Standards (who might be interested in pursuing a criminal case against the company) and a solicitor (to advise you as to whether you've got a valid civil claim).