Try to call the Singapore number during Singapore working hours and hope for the best. You are KF EG so you should be routed to KFCC (KF Contact Center) and one would hope there are agents around there that still know how this is done and are willing to do it (the problem may lie with the latter part). As SMK77 said, definitely possible without extra miles under existing PNR so the answers you are getting are off. Even if they were not "encouraged" to do this any longer (based on internal guidelines, not saying that is the case, just a possibility), then they should just say so instead of confusing customers.

The only scenario where you need all the miles again is if an entirely new waitlist with a new PNR is created and for that (assuming waitlist space is available) you don't need to call in and can just do it much easier online. Good luck, in the past persistence has paid off for some posters. YMMV.