I accidently deleted one of my main citys - started abandoning one i was converting for farming, got called away, and when I returned and put in my 2nd security password - out went my main. When using the 2 password system, when the second prompt comes up it doesn't say which city is being abandoned like the first prompt does.
I wrote them and to my surprise they responded - although they said they couldn't fix anything that was my fault. This isn't your fault, you got caught by the service thing - so write them and write to report a bug - maybe you'll get lucky. They don't usually accept responsibility for much - but the only stupid question is the one that's not asked (as my Uncle Nick use to say Luck!