Fill out the form (https://support.southwest.com/helpce...ent-or-voucher) and see what they say first. You may need to follow up with a letter and receipts if you feel the compensation offered is inadequate.

The other thing I would point out here is you had two seperate reservations (one DAL-DEN with your companion and another DEN-SMF alone). As a result, it may have not occurred to the CSA in Dallas that you were self-connecting on to SMF in DEN so they didn't rebook you or advise you of the possibility of misconnecting before you departed Dallas. The point of the companion pass is for your companion to accompany you on a trip, not to take advantage of hidden city ticketing to get a free trip to a different destination. This may be the major flaw in your argument for compensation related to the overnight stay. The $50 voucher was likely for the delay and inconvenience on the DAL-DEN flight.