Momentum pathetic service for authorisation for hospital cover

I was with Discovery medical aid for 19years moved to momentum in July with no waiting periods and now my son was not.well took him to the dr and he has to go in for a day procedure They are refusing to.give authorisation we are booked in for tomorrow morning booked for our covid tests and even took the test now we awaiting results and momentum is being difficult they have confirmed in writing that there will be no waiting periods and now this It is one of the pmb so what is the issue A horrible experience .and no one can assist there's just no response