Hypothetical: "Alice Corp"(hereafter "A") rents things(what they are should not matter, as much as possible, e.g. not housing units as those tend to be tightly regulated). "Bob B. Borrower" (hereafter "B") is their customer, who rents items from A with a contract, which specifies that the replacement cost of the rented item, should it not be returned in good condition is $100.
B rents something from A for a specified period of time(say 1000 days), at which point he must return it. B is charged $1 a day rental fee. B has the option to return the object before the end of the rental period, in which case, he will only pay a prorated amount based on the time he actually had the item.
The thing is damaged by a lightning storm, an act caught on video by an indisputable source, on day 500 of 1000; therefore, B owes A $100. B goes to pay A on the 1000th day, at which point there is a disagreement. A and B agree that B owes $100 for the replacement fee, as per contract. B holds that he owes $600, $500 for 500 days of use plus $100 for replacement. A maintains that if B paid on the 500th day, $600 would be the correct figure; however, since B neither returned the item nor paid the replacement fee (nor made arrangements to pay in installments, etc.), the rental was still in effect, and so A says B should pay $1100, $1000 for the 1000 days, and $100 for replacement. The barebones contract says nothing about this
Who is correct?
Note: This is a hypothetical situation, so any law system, etc. is acceptable. An ideal answer would be applicable anywhere, but feel free to answer using a specific one.