Mont. Code Ann. § 33-22-123

If an insured pays a premium in advance for coverage to any disability insurer licensed in this state and the insured subsequently cancels the coverage, the disability insurer shall refund the unearned portion of the premium. The disability insurer may consider the premium to be earned only on a calendar-month basis. The disability insurer may not charge the insured any fees or penalty for canceling the coverage. This section does not apply to a short-term disability policy that has a duration of 6 months or less.