Go to a third party company and let them pick it up for you. You'll lose 25% of the fee, but they should be more persistent as it's their business to do this all the time.

That's what I did with the last one with AY after they refused due to weather two days prior to my flight delay. Don't have the results yet, but was more hassle than I could continue to chase (especially with five week waits per reply).

G'luck.