Minn. Stat. § 237.06: RATES AND DEPOSITS.

It shall be the duty of every telephone company to furnish reasonably adequate service and facilities for the accommodation of the public, and its rates, tolls, and charges shall be fair and reasonable for the intrastate use thereof. All unreasonable rates, tolls, and charges are hereby declared to be unlawful. Any telephone company may include in its charges a reasonable deposit fee for facilities furnished.