Refusing to change debit order details

<p>I recently took out a contract with MTN at the glen shopping centre. I called the ********** number to change my debit order details as my bank card got lost and I got a replacement however when I called this number they told me they cannot change my debit order details I must call the store. I then called the mtn store at the glen shopping centre and they told me I must come into the store or dial 808 which referred me to the store. Why is it such an issue to change debit order details? I have long working hours and cannot go into the store during the week and would like to change my debit order details before my debit order goes off as unpaid. </p>