However, it does not rule out that when you signed the contract at that time, there were additional clauses in the insurance contract that could not be surrendered. I suggest you read the insurance contract carefully, especially the special agreement column. If not, call the insurance company. If not, go to the CIRC and complain to them.
The reason why they don't want to surrender their insurance is that when they apply for insurance, their agents get a higher commission. As soon as you surrender, the insurance company will pay back the money.
Generally speaking, you can surrender, but you will lose the handling fee.