While we don’t know the specifics of your insurance plan, we are not a healthcare service, so it is unlikely you will be reimbursed for the subscription.
You can cancel whenever you wish and your service will expire at the end of your current period. If you subscribed for six months, it will expire at the end of the six-month billing cycle. If you subscribed month to month, it will expire at the end of the monthly billing cycle. You will be able to continue using the service until the end of the period.