I bought skips whilst already having 3 free ones, I skipped the 3 then had no skips. I should have 3 left (what I paid for)

You can only have three at a time, I'm pretty sure. If you use two then buy another three, you'd still only receive two for three total. I feel perhaps the button should not be pushable whilst a player still has all three, since they can't be stacked anyway and reset each day.