Can I buy medicine when my social security card is stopped?

After stopping paying social security, if there is a balance in the medical insurance account, you can buy medicine at the medical insurance pharmacy until the amount in the card is used up. In your case, there is no balance in the medical insurance account, so you can't use the social security card to buy medicine. Although your friend hasn't paid the medical insurance fee for many years, there is a balance in his medical insurance account, and he can also use his social security card to buy medicine at the drugstore.

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