I've always just walked away, but usually the amounts are lower than what you are describing. Do you know how much of that fare was from the outbound and how much from the return? The return portion is almost certainly less than the cancellation fee, most likely. You also forfeit any amounts pre-paid for seats, bags, etc.

I dunno if they'd do this but they also might pull a difference-in-fare bit by saying you're fundamentally changing the RT to a OW so they have to cancel the WHOLE thing, charge the $119, and now you've got $34 credit but no ticket. Would the $34 buy a new one-way? Calling the airline could make things worse for you.

It's because of scenarios like that and the slim chance of things being made any better (but they could be made worse!) that I tend to minimize and try to avoid human contact in that area. Heck, I started my travel career at a time when double hidden cities were possible (like using SDF-ATL-MCI-ATL-SDF as an ATL-MCI RT, something you couldn't do now), so that was a course in human-element avoidance.

The systems with changes or refunds are definitely NOT designed for your benefit and are one of the airline's more lucrative profit centers.