While I totally sympathize with your situation, I hate to say it but their software probably caught up to you. Last year I reached GM mid-week and as we all know DL does their status run over the weekend. I spoke to a SMS agent as I had a flight scheduled before the weekend and wanted the 100% GM matching bonus plus the higher status for upgrades as I hadn't cleared yet. I was told that I would have to wait until the GM status was reflected in my account that weekend. Much to my surprise when I went to the airport and printed my boarding pass it stated that I was GM again. Did the SMS agent do something to my account after I had completed the call? I will never know, but I benefited by some sort of quirt in their system.

I would simply chalk this up to a learning experience for the future, and never assume anything out of the ordinary will happen unless you have it written on a piece of paper or email confirming that it is ok.