Plantspot App a rip-off

I'm a tour guide and was trying to identify a particular plant. I came across the FREE Plantspot App - and suddenly I had paid over R1000 for a years subscription. I do not know how to cancel this as there is no contact. What irks me is that the field for the free usage was not highlighted. I want to opt out and there is no way to do so. Rip-off!!!