Touch tone is not recognized after call connection is established

I signed up for Verizon Home Phone service (incl Long Distance) over a month ago, but from the start I have been unable to make any calls that involve entering touch tones to navigate the call menu.

I tried using a Panasonic phone system as well as a Uniden phone system (DECT 6.0) but both suffer from the same problem. I also have an old LG Slimline phone that suffers from the same issue, so I am now quite suire that this is not an issue with the phone but rather with the line itself.

I ahve DSL internet service and therefore am using my phone through a  filter provided by Verizon.

I saw a similar question from another user last year who received some advice about some old copper wires and ONT, but seeing as how I am not technical and not knowledgeable about all this stuff, am hoping for some simple advice that I can troubleshoot with.