Discovery Card
Interest charged on R2.00 short paid

In December i paid my discovery credit card on the 28th Dec 2012 the amount of R5063.03 and in error as amount should have been R5065.03 Which was a R2.00 SHORT as i made a type error. (payment was due on7/1/2013) - This month Discovery charged me R123.39 interest on this short payment, which i queried and after 3 phone call to the call centre and a week later i was sent a details making up the interest - I contacted the manager Nabantu Mokoea explaining the problem - She informed me that they would credit the interest ONLY IF I SIGN A MONTHLY DEBIT ORDER FOR MY ACC- I informed her that i always pay my account in full and on time for the last 5 years and have a good account with them she agreed but will not credit the interest until i sign the Debit order - i think this is very bad to insist on a DO before crediting my interest - please advise what my options are thanks