If you bought it on a credit card or using PayPal, update your ticket and tell them you are going to request a charge back if they do not honour their own offer.
Unfortunately, the customer service team have a poor reputation based entirely on their own actions.
They do often (not always) act when the above threat is mentioned though.
I would also (do both things) write up a text document with each qualifying point they say you must meet with your qualifying response next to it, showing that you meet each one.
Then, use their webchat service and paste the contents into the window.
Sometimes the webchat team, when faced with undeniable evidence acts on your behalf.
Again, sometimes.
I have no idea what goes through their minds when they randomly deny evidence, facts, and reality, but - too often they do.
Be persistent.