Chill made some very common business mistakes -- no focus and no quality control. Sande had a love of frozen yogurt, but no knowledge of the product beyond the fact that she enjoyed eating it. When it didn't work, instead of focusing her business and making the product better, she just kept adding more and more products to try and increase revenue.
The other huge problem was Sande wasn't in her business as much as she needed to be. Thus the staff could do whatever they wanted because there were no rules or consequences. All of this needed to change.