Cannot dispute a debit order under R200 on my Capitec banking app

Hi I have a complaint about the Capitec banking app, I have reversed two debit orders from 1Life in April 2018 and stopped them using the app. Now in May 2018 they still went off and when I try to dispute the debit orders the 'dispute' and 'stop' buttons are grey in colour as compared to the 'back' which is black and the only clickable button on that menu. Now I do not really understand why I would not be able to dispute debit orders that are under R200. I do not have time to go a branch for such things. And another thing, only Capitec Bank cannot assist with debit order reversals over the phone, why is that?