Glad to hear you re-discovered to check that first. That's T-Mo Int'l Helpline is toll-free if calling from a T-Mo line/device, although in your case - might not be the case. Go use Skype, Google Voice, Talkatone or another VoIP to call in and speak to them. Last time I used the "Chat" feature, I was able to swap out Sim card needed for iPhone use.

I'm afraid, however, if the Chat rep said she cannot pull up your account info, etc. - that odds are that your Sim cards had expired already & useless with the (once valid) mobile # assigned - if it's more than 60 or 90 days (I don't recall off hand) it cannot be re-activated, any & all stored values are gone. It happened to one of our lines, managed to keep the phone # and Gold status, lost all the unused balance but refilled it & still going - $10 USD a year, one of my emergency phones (no internet access )

Unless you had refilled it within the last 3 to 6 months and/or have a large balance for automatic debit/recharge every 90 days, the Sim cards are 98.5% expired, I am afriad - sorry. Going to need new ones. You will most likely need to wait till landing @ LAX and go find/buy a new prepaid T-Mo Starter Kit & activate. If you need navigation to the hotel from airport, why not do an offline map download first or use one of the free offline navigation app for iOS. You will be a taking a shuttle bus from the airport terminal over to car rentals, most near Century Blvd. and if it's a place like Hertz, they have self-service kiosk inside that will print GPS driving direction for you - that will get you to your nearby hotel also.

From the hotel, it's a matter of finding a T-Mobile retailer/agent nearby, or, head to a Walmart location where you can pickup, as an alternative, MNVO like StraightTalk as they have starter kit with sims for use with AT&T and for T-Mo networks. Let us know.