Dear Pueng,
Social security number is 13 digits + 2 digits key.
When the social security number starts by 7 or 8, it means that it's a temporary one. You only can open an ameli account (the account you tried to log in from the main website ameli.fr) with a permanent social security number (starting by 1 or 2).
If you have a permanent social security number and cannot apply through ameli like this : "la création immédiate du compte ameli", you can also apply through the FranceConnect application with others user's credentials, like tax office for example.
Due to the current situation, the English speaking line is not available. If you can't apply through FranceConnect and if your situation is really urgent, I advise you to contact the French line (by dialing 36 46) with the help of a friend.
Have a nice day.
