Question Summary:
Who should pay my fathers account?

Question Detail:

when my father died , he had a phone account, which he opened for my sister , she continued to use the phone and ranked up a high bill of 10.000 , she did not inform us . we recently found out.
 
who should pay this bill
 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykumwa-rahmatullāhiwa-barakātuh.
If your father opened up the phone account on his name for your sister, his estate will be responsible to pay the account due until his death. Your father’s estate will not be responsible for the usage of phone after his death. If your sister used the phone after his death she will be responsible for the bill after your father’s death. (1)
And Allah Ta’āla Knows Best
Zakir Husain
Student DarulIftaa
Michigan, U.S.A
Checked and Approved by,
Mufti Ebrahim Desai.
 
(١)فلو كان مال مشترك بين اثنين واستعمل أحد الشريكين المال في الخصوصات التي لا يؤذن له بها شرعا كان غاصبا الخ وكذالك لو باع أحد الشركاء حصّته في الدابة المعلومة من أحد و سلّمها له بلا إذن الآخر كان ضامنا حصّة الشريك (درر الحكاّم شرح مجلّة الأحكام ص٤٧٢ج٢ العلمية)