“Citing 29 U.S.C. § 216(b), this court has held that ‘[r]easonable attorney’s fees are mandatory’ when a court finds that an employer has violated § 206.20. Section 216(b) also requires the district court to order the defendant to pay the costs of the action. Although the district court has discretion to determine what is reasonable,

“Unlike credit card issuer fees, which every employer accepting credit card tips must pay, the cost of cash delivery three times a week is an indirect and discretionary cost associated with accepting credit card tips. As the district court noted, this cash delivery was “a business decision, not a fee directly attributable to its cost

“[Defendant] was not acting as AUM’s agent in any respect. Instead, [Defendant] was AUM’s customer. The proper description of the facts here is not that [Defendant] was acting as an agent of AUM, and AUM was passing on legal advice to [Defendant] in the context of a principal-agent relationship; rather, [Defendant] was AUM’s customer, and