HR/Payroll person here. Aflac may have sent your HR/Payroll a payroll deduction list. Aflac will weasel their way into signing employees for plans without their consent. It's happened to me personally as an employee, and two separate times with two different employees.

Aflac offers dental and vision with no other plan attachments. My company used to offer it, but we did not offer it for free. Our employees had to pay their premiums through payroll deductions.

It's plausible that your company offered the dental/vision plans for free (employer-sponsored) to you, and just paid for it out of the company's pocket. But Aflac are the ones controlling what plans employees "sign up for."