I applied for the Hong Kong and Macao Pass in Shenzhen, and received a text message reminding me not to buy social security for one year in a row. Actually, I've handed it in for three years.

Three years doesn't mean continuation. Maybe it broke down halfway?

The most likely situation is that the company's account balance is insufficient occasionally, the local taxation bureau fails to deduct the money in time, and it is not transferred to the social security bureau in time after the deduction. When the local tax bureau makes up the deduction and then settles with social security, it has exceeded the settlement period of last month, and the social security system records it as "paying back". This leads you to think that it is a continuous payment, but the record of the Social Security Bureau is to pay after the arrears.