After monitoring this thread and some other sources, I took the plunge a few days ago and switched from a basic AT&T plan to a Simple Choice plan and an iPhone 5s, our first time ever with a data plan.

After a day trip to Canada we flew to Bangkok and from there we're going to the Maldives, which is excluded from the list of cheap countries. I'm trying to figure out two puzzles and am asking for advice.

T-Mobile tells me I have already racked up $4.40 in calling costs. I called a rep to find out what caused that and she can't tell me for "reasons of privacy." I haven't used the phone all that much and I suppose it's possible I've already used 22 minutes between Canada and Bangkok but I doubt it and they haven't been posted yet. My first bill is already posted but these calls occurred after that. How soon will I be able to see the charges?

Second, when I mentioned to the rep we were next flying to the Maldives she strongly advised me not to turn the phone on, even after I told her I had been planning to use hotel Wifi. Why would that incur T-Mobile costs if it's on WiFi?

I would greatly appreciate anybody who can confirm whether she's right or wrong about that.

Thanks in advance.