If you are following a non-initial programme, then legal proceedings to the CBE and appeal to the CBHO are not open to you.
However, the EUR has a Dispute Resolution Committee for Non-initial Education (GNIO). Whether you can appeal to the GNIO depends on the Teaching and Examination Regulations of your study program. If you have any doubts, ask your Examination Board or the GNIO via firstname.lastname@example.org about the competence of the GNIO in your dispute.
See below for the GNIO Regulations.