How to prevent companies from paying social security?

During the service period, regular units will definitely not stop sending. The social security bureau will find out or you can go to the audit department to complain about the unit. In the end, no matter who asks to stop sending, the responsibility lies with the unit.

Let the unit handle long-term medical insurance in different places, choose the hospital where you live now, and then go to the Social Security Bureau for reimbursement regularly.

Transfer in different places requires the unit to issue a certificate of dissolution of the labor contract. I took my ID card to the Social Security Bureau to issue a payment voucher, and after I started to pay in the field, I could hand it over to the social security bureau that participated in the insurance.

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