STA Travel - Deceptive Marketing Practices (Anything to Make a �)?

Belle at the STA Travel - Victoria office told me that she had the lowest rates. They had many signs in their office touting a price guarantee. When I got home, I saw that an extremely similar package was �200 less. The manager, Dom, said that I should never believe anything a salesperson tells me. The area sales manager, Kate M, said that she made all of the decisions for STA Travel and that they would not refund me the �200. She said they would not do anything. She also added that at the time, STA was offering me the lowest price. I said we could easily prove that STA does not offer the lowest price. We could run a price comparison right then and show that for the same parameters, a cheaper deal was possible. She refused. I noticed that they don't seem to do the same volume of business they used to years ago. It's not a surprise given their customer service. Any suggestions on how to deal with these people?