Money that has been deducted but not replaced

Hi I've got stuff from checkers60sixty and every time I buy then a 15% extra gets taken off which they say gets sent back.ive haven't seen any of my money being sent back and 1 Friday a R240 was just deducted from my account by them and I haven't even bought anything on that day.ive emailed them and phoned them so many times then I get told they are investigating it and will be in touch.