Mobile App Immobilized

I am experiencing extreme frustration with the Absa Mobile Banking application. Everything is great, but the purchase function for airtime as well as the prepaid electricity is driving me up the wall. It almost never works when I try use it... It is such a convenient service (but at the same time a very common service offered by banks), but its not adding any value to my life. I either get a "Temporarily out of order" or it simply remain pending my requests or drop-down toolbars do not work... Am I doing something wrong or is there some work to be done on the App.?