This number is registered to you Apple ID, but is not associated with the phone.

Hi I recently traveled to Bangladesh from the USA to visit family. I had to change my sim and get a new number because I’m obviously in a different country. But I received a notification saying that my USA number is still being used for the account but it’s gonna expire for the phone in the next 6 days. Is there any way to extend this? I only have 14 days till I return to the USA? If not, what does this entail? Will it go back to normal if I put my SIM card back in?