Zorak

1. For next time, if you can get to wifi, Skype or Google Hangouts Dialer (not the same as Google Hangouts) are good solutions. Or if you have cheap international data (e.g. Google Fi or T-Mobile), using either of those two apps is cheaper than an actual phone call.

2. I can only tell you that, on my way back from SIN-NRT-JFK-SFO MR in 2015, I tweeted what was then @ DeltaAssist from the NRT Sky Club and they were able to process an RUC upgrade for me on the JFK-SFO leg (I didn't have GUCs at the time).

Had your entire itinerary disappeared or just the last segment? If the last segment dropped off, that would suggest your RUC had cleared and the rest of the snafu is symptomatic of the ticket not being reissued.

Did they pull an RUC? I think your only real damage is if they burned an RUC but due to lack of reissue or whatever you still flew in C+. In that case you have a pretty good argument for getting your RUC re-opened (though maybe they'll throw in some pesos for your troubles too).

It's annoying both the GA and purser think C+ is an RUC upgrade but that's a separate issue (worth commenting on perhaps but maybe separately so as not to distract from the RUC issue if there is one).