After a little more digging, I've found that the deal NYMEX was referring to  is the same one we dealt with a month ago.
I spoke with Tracy Green, one of  our contacts at Avista, and she had been dealing with the same issue all day.
Apparently, when Avista first incorrectly reported that we hadn't made a  payment, it set off a domino effect of doubts that seems to still be falling.
So NYMEX called EDF Mann, our futures clearing broker, today to assure that  payment would be made today.

EPMI-Avista Futures Contract
After a little more digging, I've found that the deal NYMEX was referring to is the same one we dealt with a month ago.
I spoke with Tracy Green, one of our contacts at Avista, and she had been dealing with the same issue all day.
Apparently, when Avista first incorrectly reported that we hadn't made a payment, it set off a domino effect of doubts that seems to still be falling.
So NYMEX called EDF Mann, our futures clearing broker, today to assure that payment would be made today.
digging ve tracy green contacts mann futures clearing called edf hadn payment set domino effect doubts assure deal nymex referring apparently avista incorrectly day