After service, landlines backfeeding house phones have interference

On September 20th a Comcast service technician came out because of pixelated TV channels and freezing up. The tech said there was an amplifier on the line that evidently was bad. He said we shouldn't need one and checked signal strength.  It was BAD. It was 18 dB at the central connection and only 4 dB at the house.  So he put on a different amplifier and it worked.  He then said he will put in an order for a new line to be installed. That was done 2 weeks later. HOWEVER, my home landlines NO LONGER GET A DIALTONE. Either it's silence or busy signal.  I want to find out if they removed the amplifier from the outside box when they replaced the cable to my house or is it still there.  If they took it, NOBODY came inside to remove the power supply.  I am thinking that whatever the type of amplifier that was added on 20 September is messing up the telephone lines too. If I don't need an amplifier with the new cable, someone needs to remove the power supply from inside my house and make sure the cables are reconnected correctly because the technician did end up putting a splitter behind my TV set when he added the new amplifier.  I think he said it was an "EQ amp" but I may be wrong. 

We can only use the phone that is directly connected to the phone port on the Modem and that's in the basement. It used to work fine until the TV signal issues.