As a mechanical, you were due a reprotect on an alternate carrier, and you should have demanded a voucher at that point, point of origin or not.
A strongly-worded letter to General Counsel (not Customer Relations) is in order. If no response within 14-days, off to Small Claims Court you go to file. The Court will advise AC of the pending court date, at which time Counsel will arrange to settle with you...if they don't, it is extremely rare for any large company to show their faces in Small Claims, so you win be default...and have the fun then of executing the judgment.