INCORRECT BILLING

I took a loan with bridge loans and was paid out the amount of R5000 on the 12th of April 2016. On friday 15th April 2016 i requested a settlement letter , which was had a breakdown of R5000 loan - R626.89 initiation fee of R626.89 and interest on the outstanding balance of R5626.89 @5% which is a total amount of R5908.23 , so how do I pay R6058.32 . Please explain as I disagree with this calculation as I feel i have been overcharged by R150.09