Birth proof rejected for Social security

Hello,
I am an international PhD student. I have applied for French social security but I do not have a birth certificate from my home country. The only birth proof that I have is a birth affidavit which I have submitted to CPAM along with its sworn translation. However, it has been rejected.

I have also contacted my embassy regarding this issue but they are unable to help. I quote their response as follows :
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owever, as you have mentioned that this document has already been rejected by the concerned French authorities, we regret that the Embassy may not be able to issue an alternative birth certificate based on civil birth registration records that are not available in its system.

You are advised to contact the concerned French Social Security authorities (CPAM) and request written clarification regarding the specific type of birth certificate or supporting documentation they would accept in your case. You may also enquire whether any alternative document or procedure is available where a civil birth certificate cannot be obtained.

Please note that the acceptance of documents for the issuance of a French Social Security Number is determined by the concerned French authorities.
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Is there any other document that can be accepted ?
Thanks and regards
Max