I had economy class tickets to travel from Dallas-Fort Worth to Abu Dhabi and then on to my destination by Etihad Airways for August 18, 2017. At the gate in Dallas-Fort Worth I purchased upgrades to business class for both legs of my journey. I paid about USD 2500 for it. A couple of hours after I purchased the upgrade, the flight to Abu Dhabi was cancelled because of technical problems with the aircraft. Etihad rebooked me on another flight for the next day. However, they rebooked me in economy class and they completely ignored the upgrade I had purchased a few hours earlier. I flew the rebooked itinerary the next day in economy class.
I have contacted Etihad customer service three times requesting a refund of the money I paid for the upgrade. The response I get each time is that they have no idea when the money will be refunded but that the money will be refunded "in due course". It has been a month since the cancelled flight and I still have not received a refund.
How can I escalate this issue either to someone within Etihad who can act on this quickly or to some independent authority who can make Etihad move faster on this? Do I have any options other than going to a small claims court? In case it is relevant, I live in the U.S.
Does Etihad ever refund money in such cases - has anyone been in a similar situation with Etihad?