Are the bills for the five phone numbers belonging to a deceased person, which are sometimes delayed in payment, considered a debt?

The heirs or relatives must pay the phone bills of their deceased relative that result from their usage after his death. As for the bills due before death, they constitute a debt upon the deceased that is to be settled from his estate. Ownership of the phone numbers should be transferred to whoever uses them to avoid ill-suspicion about the deceased and other harms.