No claim payout

I moved from Topmed to a more expensive medical aid to get better service. I took the little one to the doctor for tonsillitis on the 07/02/2018. I got informed they will not cover this as this is part of respiratory tract infection (Common symptoms of an upper respiratory infection such as a cold include a runny nose, post-nasal drip,cough, and nasal congestion) exclusion. when looking up, nowhere on the documentation provided to me did this specify tonsillitis is part of the exclusions. surely this is just a money making scheme to take a person's money and not cover any valid expenses.