The phones worked last night, this morning nothing

Could be line cord connection at base or other wiring issue. Do you have a different phone(s) at same location that work?

If you have a known good phone, the simpler the better, unplug all other tele devices at your location and verify the know good phone works?

it rings so that indicates that the land line is ok
for a quick check see if you can borrow a neighbours phone and plug it into the wall socket
If you get a dial tone then , the problem is your phone
if you do not get a dial tone , call the service provider and report a faulty service

Ringing is assigned in system programming, very little chance it was changed by mistake. If Do-Not-Disturb was turned on, that could make a phone stop ringing. If it's just one line on a phone, maybe the system got put in night mode by mistake and night programming isn't identical to day ring. If you have direct access to the phone line check it for dial tone. Often virtual lines are used and you can't check for direct dial tone. On very rare occasion the ringer stops working, which can't be fixed.

indicates that the phones are faulty
the land line carries adsl and phone at different frequencies so as the internet is working so the land line is good
check that the internet and phone line is connected into the correct sockets on the line splitter before the land line connection

I gather you have the setting for tone and pulse set to tone? Also are you aware the ringing tone is generated by the phone company? When you dial a number and it connects, the phone provider sends the ring signal to the dial phone and the ringing signal to the dialing phone. Do you get a dial tone before dialing?

We called the phone company.....There was a problem up on the telephone pole. They fixed it, no charge.

Is this a system phone?

It sounds as though your set is not programmed with a line appearance. and line preference is not set, this can be set for intercom, or a line or nothing when you pick up the phone. You can do a pick up code to answer until an appearance is programmed on your set.

if there is no dial tone that means that the connection is not being made when you pick up the phone hence you cannot answer nor can you get a dial tone
the fact that the phone rings indicates that the land line is good so the fault is in the phone itself