Exactly. Please OP, don't take it the wrong way but when you deal with people from whom you need a favour, my sense is that referring to an incident that is completely unrelated and is 'done and dusted' will not get you the sympathy you might expect but instead make the person you are talking to feel threatened for something they had no part in.

Just explain what you booked, explain that with the change of time by the airline you are being proposed a 9 hour layover which you really can't fathom, and explain what would be the types of solution you are looking for (typically, can they change either of the two flights so that your layover is shortened, but if you have more flexibility than that, e.g. you prefer to fly a different day if it means a better connection, do tell them). Do tell them that if nothing else is available you would like the ticket cancelled. For 30 minutes under their 'formal' cut off point I have no doubt a supervisor can and most likely will authorise the refund.