R20.90 for 1 slice of rye bread

I had a quick bite at netcare waterfalls I still have the bill. They charged me R20.90 for 1 slice of rye bread toasted no butter and another R13.90 for 4 thin slices of cut avocado. Can this be possible R20.90 for 1 slice of rye bread. The service was extremely poor no quick bite....very dissatisfied customer.