So another ripoff by the look of it.
I have two Adata pen drives that are reported at less than the labelled size. Even if we understand that there are two different ways of defining what a gigabyte is (one uses 10^3 as the multiplier and the other uses 2^10), the size of these devices is being reported as less than would be expected.
An older model Adata drive in my possession reports as 8 GB while a modern one shows as 7.5 or 7.0 GB.
An enquiry has been made with a wholesaler to see if any recourse can be obtained.