It's been three years since the policy came into effect, only to find out that it was signed on your behalf?

These things should have been discovered during underwriting at that time.

As the insurance company underwrote the policy, it recognized the insurance contract.

So at this time, the insurance company should compensate for the accidental death insurance.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.