Perhaps I'm missing your actual requirements (based on what's been suggested below), but I've been using voip.ms for years now. They support voice and SMS, and

Perhaps I'm missing your actual requirements (based on what's been suggested below), but I've been using voip.ms for years now. They support voice and SMS, and even my bank's SMS "2FA" works with them now. They don't support MMS, however (though you may have meant that when you said SMS). SMS is available as a FLOSS app (I use the F-Droid voip.ms app), or through another portal - able to be sent/received through email, another number, or a web interface. I honestly have only good things to say about them (despite being a consumer of their seemingly B2B product). As a disclaimer, I don't work for them, have no affiliation with them, and made a point of not using any kind of referral link.