Discovery NOT consistent with payment of procedures.

My wife had undergone a painblock on her back 2 years ago. We had to pay 90% of the procedure from our pocket -when I approached Discovery last year about this and told them that the procedure was authorized by discovery before procedure, declined AFTER procedure was done and then AGAIN authorized - they said it does not matter. Someone slipped up. The reason why I say this is because my wife had undergone the exact same procedure last week and discovery paid 100% of the procedure, NO MSA were affected. How is this possible that Discovery expected us to pay 90% of the WHOLE procedure 2 years ago with Dr Dan Hugo, but last week you had no problem to pay the FULL procedure? I dont mind that it were paid in full my issue is that I now know that 2 years ago something was NOT submitted correctly either from the practice side or Discovery's side. Please advise, because up to this date, the outstanding amount has NOT been paid towards specialist as we still dont agree that we should be held liable for the cost when the procedure was authorized in full BEFORE my wife had to undergo the procedure. Discovery please advise what made you decide to NOT pay the exact same procedure done on Nikki Lombard, 2 years ago?