About My EMI Plan and My $15 plan

Hai,

I had taken T-Mobile line on 2023 January and changed my plan to $15 after few months

1.Now I am in my home country will the $15 plan will work internationally,If I made phone call to USA if it connects will be there extra charges for international.

2.What are T-Mobile International plans.

3.And Where can I see my agreement made to T-Mobile on January 2023 for specific period of time(End Date)

4.What If I don’t pay for my plan in  June and July