Talaaq

Dear experts, plz help me.My friend who was deserted by her husband called me today and was very tensed.her husband sent registered post but didnot mention his name as sender,but fc address was there.she was not available ay home so didnot take it.she fears if it could be divorce papers. plz expert tell us if the talaaq or divorce is valid if sent through registered pos .she dorsnot want divorce....how to prevent it, tackle the situation plz tel if she should take d post or not....ciz she fears it to be talaaq papers...eill the talaq b valid. Thank you. Please reply and help us.