Ripped-off by Starke Ayres

I have chosen this forum as Starke Ayres does not seem to directly accommodate complaints online: I recently purchased 10kg Bio Ganic Lawn fertilizer from Starke Ayres and when it came up as R219 at the teller, I felt a bit **********........until I came to feel REALLY ********** after seeing the exact same thing (10kg too, not the smaller one) at my local hardware shop for R160 (37% more expensive, Starke Ayres, really!? Note that I have confirmed this price telephonically with Starke Ayres, just in case it had been a teller error). Another retailer is also significantly cheaper (R180). Now I know Starke Ayres has a reputation (amongst the people I have spoken to, at least) for being too expensive, so I would expect anything between 10-max20% more expensive, but this is at an ugly level which makes me not want to go there.