how are the roots?! The cells in those mushy leaves are dead so cut those parts off. Check if some roots are frozen and cut those off. Looks like you will still have 1/2 of the leaves and some good roots to work with, just grow it like ordinary and it should send a new leaf from the top. It will grow well in that sphag moss.
I had a phal bellina that got fried in the July heat in shipping before but I didn't change it to sphag so it died. However the vendor replaced it and the second one and it got fried too, but I grew it in sphag moss instead and it is growing new roots and leaves Similar type of damage to yours, the dead parts there traslucent. I have no clue why the guy sent it in coarse bark knowing that it will take some time to get into Canada from California and the weather is hot! Then I guess I have no idea why I bought that from the states when they aren't that hard to find.