I looked back to see if this had been suggested and didn't see it, if it was, mea culpa.
You might want to consider an extra heavy dosage of pectic enzyme. I had a pear wine once that I added pectic to the mix at the start, normal amount and never could clear, finally added a triple dose of the enzyme twice and it cleared up as clear as a bell. First time helped a little bit, then second everything was gone. I tried the test Jack Kellor suggests for pectic haze and they failed, but I was desperate. Pectic enzyme is one thing you almost can't overdo in adding, particularly once alcohol is present. Might be worth a shot. I did add it the way Jack Kellor suggests to clear a pectic haze, something like pull some amount out, add all your enzyme to that, stir, stir, stir, wait 30 minutes, stir more for a total of 3 hours or something like that. Then into your wine, wait 15 or 20 or maybe 30 days try again.