Getting credit for flight taken (Enrich # missing from booking)

My Enrich number was missing from the booking & I didn't notice until I had taken first leg of the flight.
I contacted MAS / Enrich using their "missing miles claim" link
I got a reply saying that there are 6 "rules" to follow to ensure account will be credited
but most interesting - said that since the Enrich # wasn't in their system for that booking then there's nothing they can do to credit the flight....
This doesn't seem fair to me - I booked/paid for the ticket & I have an active Enrich account...
Comments/possible solutions???
Thanks