Transferred money to my loan account

I decided to pay a balance towards my personal loan account so that I can finish and close the account by the time when the outstanding balance would go off by due date - when I checked my account statement, I saw my account is in advance I immediately phone in and spoke to a consultant and he said they will deduct the monthly installment each month from the amount I deposited towards my loan account? Why would I deposit money into my loan account for the monthly installment to continue as normal.

I want to settle my loan account and close the account asap!!!