Help pls

Hello folks, I’m currently on a business trip, and my old T-Mobile sim was virtually unusable overseas, so I decided to get on the best US mobile plan. I let the man assisting me know I was traveling abroad, and he helped me through porting my number out. What they didn’t tell me was that they cannot activate it if I’m not in the US. This is my first major business trip, and I’m currently out of luck, if someone could please help, that would be greatly appreciated.