My number/service cancelled, how to proceed?

I moved to another country but kept my T-Mobile number and sim card (my phone has a dual sim). I stopped topping up each month as I wasn't using it, but still planned to top up again when I visit the US.

My service was recently cancelled and the email just said that to reactive my line to go to the website or call. I can't get into the website without putting in my phone number, which is not recognized anymore. I just tried to call but time zone differences mean they're out of hours and it automatically hung up on me.

I’ll try to call back later but in the meantime is there an easier way to get my service reactivated?