Almost forgot... when I re-read your response I had sort of the impression you left the plant out of the pot and laying on the windowsill. I hope this is not what you did. You should place it in a plastic bag to hold SOME humidity. You'd want air movement to preclude mold, but not over drying. If you are doing the bag treatment, place a wetted (well, wrung out) paper towel in the bag, not in contact with the plant or roots, to provide moisture. It's important to keep plant from dessicating at this point since respiration is suffering. It should respond soon. Oh, and leave a vent for air in the bag.
I am going to throw a different approach at you in regards to the growing media and the culture of phallys as pertaining to this particular plant.
The use of the sphagnum and bark mix is OK for phallys! In fact I think the plant would love this combo-I may try it sometime whenever I ever get a phally to experiment with.
WHAT IS IMPORTANT is how you treat the plant in this kind of mix.
I notice that the pot is a regular pot and you have it sitting in a tray to catch water. I would dump the pot and get a net pot instead. Keep the tray and repot the phally into the same mix you are using but into a net pot instead. On your mix you may want to go with 5 parts bark to 3 parts long fibered sphagnum or even green moss (a lot of folk really think this is a bane but it is organic and has a good use). Water the potted plant and lift it up to see how heavy it is. Even weigh it if you want to have a record to refer to. Then let it dry out to at least half its weight or even less while maintaining humidity (by sitting on a tray with gravel and water or by misting lightly during each day-this could be iffy for a plant in your state).
I would recommend that you get another phally and try my approach. Find one with a flower similar to your plant. (Personally I would toss your plant-sentimental value and all-replace it and let it be the symbol of your affection instead-hey it would be healthy!!! )
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T-Man... becareful with this recomend. In areas where humidity is low, that;s safe. I assumed this grower was in an area where either she grew it wet or where the humidity was high (or both). In that case the only safe bet is NO sphagnum. Sorry to disagree but I call 'em as I see 'em.