FNB promising international lounge access with Visa app but failing to deliver

We were really excited to use the international lounges with our global credit card. We downloaded the Visa travel app and presented them to the different relevant lounges around the world. Most of the lounges on our trip denied us access because they were at capacity. In South Africa, when we asked if we could use the international lounge, we asked if we could use the Visa app. They said no and said to use the FNB app. Despite that we were still charged R960 for myself and my wife. When we asked about the charge, the staff complained to us about how FNB promises their clients lounge access to international lounges using FNB but never informs them of it. Overall a bad and expensive lesson due to overpromosing and poor communication, leaving a sour taste in the mouth for what we were expecting to be a delightful experience.