Outside the US

I just recieved my first Disability SSI check in the mail one month ago. I am outside the US visiting a friend and will not be back for a few months. What can I do about the checks I recieve in the mail? My grandma wont sign them and says all I can do is forfeit them. She thinks it is illegal to be outside the US. What can I do?

Can someone in my family sign it for me. Can I still recieve if I am outside of the US?

Thanks

Shirley Grossman

Shirleyshirlzee@aol.com