Settlement over charged

Went into store to settle account balance which is 10 months prior to last installment. Account balance 23/10/2015 R6 327.54 , i had to pay an amount of R6 789.74 when i queried it the accounts advisor at the branch said that it was interest and other that is still charged for the months that i will no longer pay.<br> does this mean that you don't qualify for a discount on a settlement.