In a lot cases it's hard to imagine that the person asking for help doesn't see that they're pretty much the major cause of their problems and also the main reason why other people are struggling to provide constructive advice.
There seem to be more and more people who behave in a completely unreasonable fashion yet are completely oblivious to the fact. These people are usually the first ones to say "its not my fault" as well.
I have had this sort of thing happen to me a number of times with companies. I never blame the customer support person as common sense should tell you that they won't benefit from lying to you. They get their wires crossed sometimes or perhaps they get confused. Being a vindictive **** and demanding that a complaint is raised against someone is just sad. They usually sort it out quite quickly but you might need to try again. For the sake of £300 I would phone them up and see what they say rather than throw my toys out of the pram.