You hang up to avoid a Belgacom charge, and the computer calls you back, providing you with a stateside dial tone so you can dial as if you were in the United States.
Hanging up helps the user avoid a charge.
mnli hypothesis: Hanging up helps the user avoid a charge. premise: You hang up to avoid a Belgacom charge, and the computer calls you back, providing you with a stateside dial tone so you can dial as if you were in the United States.