Context:

• Took two Aeromexico flights in November 2021, which did not post to Delta SkyMiles account
• Submitted missing mileage form on Nov. 27, 2021, received automated e-mail response with case number
• (one eternity later)
• Received response on Apr. 21, 2023 asking for copy of boarding pass and ticket receipt so miles could be credited; replied back with this information since I did still have photos of the boarding passes

I fully expect that they'll deny my request for miles when Aeromexico can't verify some information for Delta, since it has now been ~1.5 years since the flights were taken, even though all that delay is due to Delta. Does anyone have any advice on this?

Is Delta still this backed up on addressing customer service requests? Does anyone else have any longer periods they are waiting for responses?