As the title suggests when buying items on mobile it is not always clear if you have bought an item or not, or that the sale has completed.

A specific example. Buying new marks for weapon/armour. Go to upgrade armour on any mobile app version, chose best marks and list appears. Buy mark. However nothing appears to happen, particularly on a phone app version. I would expect at least some form of acknowledgement from the game that I have completed the purchase, especially given the limited view within mob apps