It is actually 20 working days, and i just researched on what should be the standard and acceptable time for complaint and issues to be resolved, a 20 working days range is the limit according to this -
Read here It could also be applicable in the gambling sector I think.
I know it can a while to wait and there is always the potential to get impatient and angry, but If the company asks you to wait within a 20 working days period to have an issue resolved, It may not actually take 20 working days as your issue may be resolved even before that time.