Vodapay app has a umber of defiencies

I try to use the Vodapay app which in principle would be great if it worked fully and was properly supported. The app; 1. Allows you to purchase vouchers advertised at a certain price but when you try to buy the deal is different. 2. Vouchers you previously bought show available on the system but when you try and use them they seem to be invalid. 3. When you place a support request you receive a ref number EC-28VS-27R19N and a promise that you will be called - then nothing happens!!