A company conducted a survey of $500$ customers who recently purchased their new smartphone model. Customers were selected at random and asked, "Are you satisfied with your new smartphone?" $85$ percent of the surveyed customers reported being satisfied. Based on this survey, which of the following statements must be true?

I. Exactly $85$ percent of all customers who purchase this smartphone model are satisfied.
II. If the company surveys another $500$ randomly selected customers, it is certain that $85$ percent of them will be satisfied.
III. This survey proves that the smartphone is of high quality.