Yea that is a big draw back on the iPhone although apparently Apple has
given in and will be adding that capability to OPS 8 this fall. Even before
the free international roaming WiFi calling to and from the US was free,
used it and still use it all the time. As for calling now I would see what
network you are connecting to and/or force it to use 2G and see if that
works. I am not an apple person so don't know how to change that stuff in
an iPhone unfortunately. I travel overseas a lot and Germany is one of the
countries I didn't have to make any "tweaks". If that was a tmobile branded
iPhone it should work.