Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Perhaps the line is indeed bad.
Do you have other phones to check the line with? or even, an old fax machine (which usually has a phone line plug-in, and a handset to listen in for dial tone etc.) ?
If not, then what is your phone line service?
And what models of Panasonic phone did you buy, that aren't working?
Some solution will be found for this problem. Please give me the info, in Reply, that I have asked about, and I will advise you further.
What phone line service company provides your phone line?