05-28-2015 04:54 AM - edited 05-28-2015 04:56 AM
Because the wiring inside your house is your responsibility. Verizon's responsibilty goes as far as the supplier's side of the NID for a landline or the ONT for digital voice. As they charged you they are saying they made a service call to repair something on your side of the interface device. As you can see they apparently charge about $180 an hour which is why it's wise to test the homeowner's side of the inetrface device before calling Verizon.
The test is to disconnect your home wiring and instead plug a phone directly into the ont or nid rj11 jack and see if you get dial tone and it works. If it doesn't then it's their issue else yours to either investigate or pay them to investigate.