Someone else asked whether she can cancel an accident policy and get her money back. The answer to both questions is that it's highly unlikely. I've never heard of a disability or accident policy that provides a money-back policy if you don't use it. But I'm not going to say that no one has ever issued one. The same goes for virtually every other type of insurance.
Insurance generally is a gamble either way.
If you don't buy it, you're gambling that you won't need it. If you do buy it, you're gambling that you will. One reason for buying it is because the stakes generally are higher if you lose the gamble by not buying it than if you buy it. Perhaps the only type of insurance that returns a payment if you don't use it is whole-life type of life insurance. And that doesn't necessarily return the payments if you don't use it.