Hi,
This is tricky, from my memory, if there was nothing to indicate that the rep is not representing the company and you had no doubt about it, and you incurred a loss, then there maybe legal action you can take against the company, this is what I remember, if I'm wrong, I hope someone can write the correct info.
there should be some conditions before this can happen, such as the person was actually a representative for the company before and acted on behalf of the company and there was proof of the relationship between the person and the company the person represented.
This is what I remember, but what I can advise you is if you incurred a loss or were affected negatively, contact a lawyer/solicitor to confirm.