I think that the migration you're mentioning here is what they market as their NGN line (Next Generation) line, which is basically a fibreoptic connection from their Exchange to the main boxes, which are strategically placed in your neighborhood, so that you're "effectively near the Exchange".
It looks like there is a mismatch in the new main boxes vs. the connection to our homes in as far as datacomm is concerned. This could be the main reason why the DSL line doesn't work but voice is okay.
Got myself entangled on this issue too. It is a good thing that I was able to get out of the contract with a couple of "bruises" as they never delivered what they promised. They even were telling me that I have problems with the pre-installed telephone line connection inside our home, which I did not allow because I know that it was done properly.
Anyway, DSL connection was down a good number of times, and max speed was only 100kbps at times. Whew!
That is why some PLDT Techs are calling this NGN as "Not (a) Good Network.