Reply to the message that they totally missed your complaint and that you understand how to use the award calendar. The problem is, the calendar is BROKEN BEYOND BELIEF.

I am having the exact same problems you are... pull up the calendar, it shows green on dates I want. So I go ahead, and suddenly it prices all flights a medium... and not just that, it gives random 11hr+ connections unless I resubmit the search 3-4 times.

I don't even think that DL knows or believes that the calendar is broken. From things we've seen from their own internal IT dept, they seem to think it is working correctly and with no problems. I used to think they intentionally left it broken to suck more miles from pax, but now I think its even worse... total ignorance of the issues.