A group of five provincial students rented a condo unit of Mary Jane for a period of one year. After the semester, four of them returned to their respective provinces and the fifth transferred to another apartment in Talamban. Mary Jane discovered that they left the wifi unpaid amounting to 25,000 PHP. The lease contract states the lessees will pay for all the utilities and services in the leased premises. Mary Jane demanded from the 4th student to pay the entire amount of unpaid bills, but the latter is willing to only pay 12,000 PHP. Which party is correct and why?