From what he is saying it is pointing to a Line problem from the CO to the house.
Since he only has DSL and no Dial Tone service, dsl filters are not needed.
But the phone company still needs a clean line .. no high resistances, no resistance
to ground (called an escape), no foreign voltages (ac or dc) and Loading Coils &
Bridge Taps must be removed from the cable run or dsl will not work properly.
DSL runs at 10Mhz or so ... call Verizon and have the tech come out ... he will use
a data test set to see the DSL Levels at the home & modem / pedestal or pole .. if
there is a line problem, he will be able to tell and refer it to whatever dept needs to
fix it, such as cable splicer or carrier tech. I retired from that company, so I know
about how they work. As to early term fee, if the service is not meeting the rate
you ordered and it is an issue they can't fix, then I would not expect a fee to apply.
But you might need to get pushy (with tact) to make sure it is waived.