1. Your mother is the insured, and she is a person with full civil capacity. The insurance company didn't lie to her. The contract she signed with the insurance contract was valid and there was no legal invalidity.

Your mother is the insured, and you are the insured, that is, the insurance beneficiary. You don't actually need to sign the insurance contract in person. Your mother will write your name and fill in relevant information for you.

If you want to ask for surrender and think that the insurance contract is invalid, your reason is untenable and the insurance company may not agree.

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