chingon

So I had this battery that I was trying to desulfate. I top it off, and measure voltage to around 10.5....two of the cells were halfway empty (water wise). I leave it for 6 hrs or so at around 4 amps. Come back, measure each cell, most are climbing to the 2.xx volt range ( i think i may have seen as high as 2.4)...but one is lagging behind pretty bad (.5 volts or so). So I let it run for another 3 or 4 hrs more.

I come back to disconnect for the night and notice shit's not going as expected anymore. 3 cells are reading 0 volts, and I'm getting 2 volts from what seemed like close to 12 at some point a few hours earlier. So at this point I'm guessing it's fubarred. Is it, or can it be brought back?