The most pleasant surprise you could give your users is not running out of funds in your Paxum account every couple of weeks.  Bells and whistles shouldn't be a priority until you've addressed far more basic issues like reliability of processing deposits and withdrawals.  At best your inability to resolve those issues makes your company look incompetent.  When you keep saying sorry and the same problem keeps happening with monotonous regularity, it's difficult for people to believe that you give a damn about your customers.  No amount of perky PR speak compensates people for the sheer amount of effort it often takes to complete the most basic of transactions with your company.