Just wanted to check in here and say that I was able to redeem the certificate. I cycled through 5 CSR before finally reaching someone who knew what to do. They deposited the extra 12,000 miles into my account and then took out 50,000 for the two tickets. No ticketing fee was charged.

Overall it was 45 minutes on the phone wasted, but I was very happy to get two tickets for only 38,000 considering the rapid decline of Skypesos.