t1wireless : On the complaint just call their service dept & tell them you have static & echo on your line.They are supposed to give you good quality voice service.I doubt if they will replace the service line to your house unless it is physically damaged .Like there are bare spots where the outer cover is coming off.
If your NID box is this old they will probably replace it.One thing the NID box has in a couple of "carbon" I think lightening supressog that wear after time.The new box should correct this.
I think you can only get a data line if you can get DSL.They won't put one in for just phone servive.There are some technecal reasons (if what I have read is correct & it may have been disinformaton to keep customers from asking for a data only non DSL line) that removing the load coils & other distance additions from the line won't help data transmission.I reall didn't understand why.
Now for the bad news the FCC only requires your voice quality phone line to be 14K so I don't know why the complaint about it corrected his speed.Make the voice quality complaint first & see if it helps.If it doesn't then try complaining about the data speed.
My internal modem usually connects at 40K but I have an external that will not connect above 28K no matter how it's tweaked so it can be the modem.But again if you can hear line problems the you have a problem the phone company is required to fix.So that is where you need to start.