I have just come back from a trip to Europe where I used my phone only in WIFI to make calls to the US. When I came back my bill was over $1000! T mobile's web site states in Making calls from Androids that:" There is no additional charge to use Wi-Fi Calling and calls to the U.S. from abroad are not charged roaming fees".
I haven't been able to get any help from customer service. They said that if the signal is stronger from Tmobile that it switches over to their service! Why isn't that informed!!!!