Seems to me, from what I can tell, you should have been awarded CRSC based on PTSD. It may be that I/we don't have all the facts to see what is really going on.
With regard to contacting one's representatives in congress, just my opinion, but I doubt if that would be helpful in this particular case. A staff member of the representative's office will contact the Navy and the Navy will have the Board write a reply that explains the process and point out that the decision was objective and that the members of the board mutually supported the final decision. That reply will be the basis for the Navy's position and what you receive from the office of your representative.
I wrote several replies in response to congressional inquiries during my Army career. That is not an accomplishment, just an experience. Not one of he inquiries resulted in a change of what we had done in computing pay or determining eligibility for a certain allowance. That of course, is different from an assessment of combat related status. However, I suspect the Navy can justify their decision as it would have been easier to approve the CRSC than deny it. The board or the Navy does not benefit in any way from denying an application.
Note: It is my understanding that the Navy board is not a contractor, unlike the Army.
Good luck in going forward.