So let's see when I get the new UM+ Jersey card in the mail if SMS works through AT&T and T-Mobile USA again (as other pointed out these carriers now block the old UM Liechtenstein cards). My local prepaid sims are much cheaper for US or Canada, but an SMS would keep the card alive if I don't travel internationally for several months. I'll post my results.

Estonian Mobiles with CBW, Enlinea
 

I have never been able to get a callback on my estonian sim card with either cbw and enlinea....has anybody? Interestingly enough, though, the pin2dest on cbw does work and my US toll free number on enlinea to Estonia does work too!

I was able to receive the callback some weeks ago, but not always. 2/3 attempts failed.