How to explain why social security cannot be transferred to the current unit?

Your problem belongs to the inter-provincial transfer of endowment insurance. There are two ways.

One way is to ask the person in charge of labor and capital in your current unit to go to the social security bureau to open an acceptance letter for you, and then take the acceptance letter to the municipal social security bureau where your original unit is located to open a transfer form, which says that if there is arrears, you should make up the arrears.

Then I'll give you the transfer form, and the person in charge of labor and capital in your unit can take over now.

Second, regardless of the original, first open an account in the current unit and hand it over to you first. Then, if there is an opportunity to transfer to the original unit, then take the transfer bill to the current unit to consolidate the accounts.

I feel that your company just doesn't want to give you no stamp. There is no freezing of funds, and it should be liquidated in bankruptcy.

If you can't transfer, you must stop insurance at your original residence first, otherwise there will be arrears. The old-age insurance of the original unit is covered by the local social security and will not be invalidated.

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