Sterns Baywest hidden resize cost.

Can someone tell me why a resize of a new ring would cost R800, and why was I not told when I made the initial lay-by that I would be charged to have the ring in the size I wanted? I mean, do shoes of a different size cost different amounts? it would not be farfetched then that you intentionally make small rings so that you can charge everyone R800 to resize? Guys, I am not paying R800 for a R200 service. Please rethink or give me back my money and I will go be shafted somewhere else.