I reserved a ticket with an agency, at that time the ticket was at $750 and I paid it for the reservation, but I didn't receive a confirmation from Emirates that my ticket had been booked. Just a week later, Emirates advertised a promotion with ticket price dropping to $540 and that's when I received a confirmation from Emirates that my ticket has been booked. It's clear the agency bought me a ticket for $540.
I'm not sure how you intend to prove that the agent bought you the same ticket (the basis of your claim); and pocketed the difference.
Consider the following:
- It is normal for airlines to offer cheaper fares on their website than agents; or hold different promotions that are not offered to agents.
- The fare type/class/code may be different; you may not be comparing apples to apples; even if both tickets are for the same class of travel.
- Rates that are available to individuals through direct booking are not always available to agents.
- The agent would have to have advance knowledge of a booking; hold your reservation till that date, ensure that they were able to book that reservation in order to take advantage. A highly unlikely scenario.
I personally have had to pay a premium for booking through agents many times.