Did you realize you made a "double post" maybe not realizing the submit worked the first time?
Similarly, it appears you purchased a sleeve of balls and then purchased another immediately after doing so... I guess it is possible you accidentally purchased 2 sleeves, not realizing the first purchase went through successfully and maybe the credit didn't show or process until after you had looked at your balance.
I know we can be critical of WGT at times, but I have never known them to steal credits.
You could double check your account transactions summary to get a better idea.