Poor customer service

In June when Starbucks opened in Illanga Mall in Nelspruit, I had loaded money onto the Starbucks app. Went to the store, app Doesn't work on their side. I said it's fine they told me it should be fine over a week. Went back the following month, their system still can't take my app to pay. Another month later which is August, same problem. Same excuse. I emailed their rewards team, they told me it should be working. Now it's November. I went there yesterday which was the 8th, SAME EXCUSE "the system doesn't work" supervisor comes over. I told him for months this hasn't been working and rewards told me it's working so why can't I use it. Same excuse once again, so I left. I have emailed their rewards again, told them they must either sort out their branch or refund me the R400 I loaded onto the app. Because I will not support Starbucks until it is sorted and I'll be spreading the word about this