Call back and speak to a different agent. Your RUC has cleared and the ticket just needs to be reissued. Say something along the lines of:

“Hi, I’m calling because I’m unable to check in for my flight tomorrow and an RUC is involved and need to get the ticket reissued.”

The agent should have no problem doing this. There is a good chance they will have to contact “global ticketing support” to do this, which can be another buzzword if you get another poor agent. Sounds like you just had two in a row unfortunately.

And lastly, don’t leave this until the airport. The airport agents can’t help with this and it will result in the same phone call, but at a very early time in the morning.