3 way calling with International Participant

[BrooklynGuy]

Recently I called my Girl Friend who is out of the country until the 2nd (me so lonely), and because of a minor credit card emergency she was having we decided to call her bank. 3 way.

I dialed the number and it connected, however the bank could not hear her or me. We assumed it was because we were calling a bank, or their automated system simply didn't support 3 way calling. 

But then a few days later I tried 3 way calling with her and her farther. he could not hear us either.

Is there something wrong with my 3 way calling or is international 3 way calling now allowed?