Files before high school should be asked in high school. Only they know that if it is lost, it can be reissued, but the procedure is very troublesome.
Self-study exam file seal
When we graduated, the portfolio was glued on by ourselves, and the teacher in the self-study office stamped it. You can consult the self-taught examination office that issued the diploma to see if it is your turn to stamp it.
Reissue method
If the talent center in Beijing doesn't accept it, after finding the high school file, put it in the talent center where the account is located together with the self-taught file.