Probably is Obitalk.
It didn't stop working, it's just that they closed their online management portal down. I only used the portal when I first got mine. It was limited in what it could do. Okay for a non-tech user, I guess. You can completely manage the Obitalk device via its web interface. You can even set up distinctive ring tones, which is handy.

I got our first OBI200 in Mar 2020, and the 2nd in Dec 2020 as a spare in case the 1st one goes bad -- which it hasn't. On sale for $64.
Our ATT wireline phone was costing $49/mo. And it was at heart voip (on DSL) anyway.
I looked around for VOIP providers and signed up with voip.ms. Our phone bill now is about $3.75/mo, most of which is the 911 service.
The OBI200 supports 4 (four!) voip servers.
We have ours set up for voip.ms (primary), and Callcentric (outbound calling only), and GoogleVoice.

voip.ms has SMS support, so we now can get text messages which get forwarded to my email address. Most but not all financial institutions can send 2FA messages. Some will say "nope, we won't send 2FA to a voip phone number."