unpaid C2+

/ʌnˈpeɪd/ not yet paid; working without payment

payoff C2+

/ˈpeɪɔf/ the return or reward from an action; a bribe or final settlement

prepay C2+

/priˈpeɪ/ to pay for something in advance

repayment C2+

/riˈpeɪmənt/ the act of paying back money owed, or an amount paid back