1. You will continue to receive money until the policy expires. 2. You will continue to receive money until the Policy is discontinued. 3. You will continue to receive money until the end date of the policy.
(1) sounds strange to me. The verb "discontinue" is normally used transitively, with the subject being the agent that causes discontinuation (e.g. "We are discontinuing the policy").
(2) is correct English. However, be sure you don't mean "until the Policy expires".
2. You will continue to receive money until the Policy is discontinued.
It implies that the policy has no defined end date. It can be stopped at any time the issuer wants to, unless there are restrictions stated in the policy.