Hi Ozhope,
Sorry to hear all this! My case was not similar to yours, but rather that the required qualifications for my profession had changed since I qualified ie the minimum level today is a Masters degree but that degree didn't exist in Australia when I qualified here. When I pointed this out, and that the fact that my professional certification body recognized my qualifications, I won my appeal.
Are you able to document that the minimum credit value is a new requirement, perhaps? Sorry that I can't really help you any further.
Perhaps someone else on the forum can help Ozhope?
Good luck!