If you choose to cancel your policy, or your insurance company cancels it, you typically won't get a refund unless you've paid the premium in advance. For example, let's say your policy term is 12 months, and you pay the premium for the entire year upfront. If you cancel your policy after only three months, your insurer will issue a refund for the remaining nine months.
If you pay in monthly installments and cancel your policy at the end of the month or billing cycle, you probably won't get a refund. But if you were to cancel your policy in the middle of the month or billing cycle, then you may get a small refund since you've already paid your premium for the full month.