The sentence you provided is grammatically correct and does not require any additional commas. It reads clearly as is:
"Ms. Benchley said that employees who deserve a workplace free from harassment should report any problems to her."
If you wanted to add a comma for clarity, you could place one after "harassment," but it's not necessary. Here’s how it would look:
"Ms. Benchley said that employees who deserve a workplace free from harassment, should report any problems to her."
However, including the comma in this case is generally considered incorrect because it disrupts the flow of the sentence. Therefore, it’s better to leave the sentence as you originally wrote it.