Slow website response

I logged on to the Vodacom website to make a bundle purchase. I attempted to buy a data bundle of R99. When I filled in the relevant fields I clicked buy now, no response from the site, I clicked again, and no response , I clicked for a third time , no response, I went back to view my bill and noticed that I ended up with three data bundle purchases of R99.No whilst I accept reversals are difficult the fact that the website didn't give me confirmation of the purchase is the reason I kept clicking. I need a resolution to the problem because if I wanted this much data I would of rather purchased a bigger bundle.