What means breakdown of cost to my account

Since last week Tuesday I am requesting a proper breakdown of all transactions including casts and interest on my account as from the last written Statement received - closing date 29-12-2018. Until today I received the 4 transaction to the account but no breakdown of the costs and interest. This is now taking more then a week and Discovery is delaying my settlement as there is a difference of R 105.30 unspecified costs to the date 12-01-2018. I am still waiting for the breakdown therefore what is costs and what is interest.