..Or - Maybe you were Testing
Bens..
jk
a) but yeah, Ben is correct - 'VoIP' is Voice (over) Internet Protocol - essentially, unless this is legacy-DSL (where both the data and voice are transmitted over (at least) 'last leg legacy-Copper', into yer house / modems..) there would be a separate Modem expressly 'for the Voice part of it', ie:
...Is this what you Have? Important to clarify, since this:
..sounds more like you have legacy-DSL (where there's a little 'filter', inline, like this:
..Or is it more of an Actual Modem, like in the previous pic?
...Either way, it sounds like the 'phone-modem' part of your set up has gone belly up (maybe..) which is certainly Possible (internet-side of the modem Works - phone-side, dead..) Just depends on how the electronics are designed in the modem..
..Could simply just be a 'bad port' (sometimes, some of the 'SMCs' (surface-mount components) like diodes or resistors, often found on the I/O interface boards of those ports, can 'go bad' (bad solder-joint, or one that has simply 'given out' due to age / heat over time, etc..) and - poof - there goes yer connectivity to Just that side of the modem.. and thus Voice...
..And while it Is usually possible to 'get a New modem' (even one You can buy..) you will Still need to get in touch with the Co, to a0 make Sure that model will Work with their service, and b) they will have to 'provision it' / plug it's 'MAC address' into thier system, to be able to address it / upgrade the firmware to the most current, etc..
..But, lemme know on the First questions, and we can go from there...
jd