Hi Quickstatus,
Since you asked, letting you know I got a reply to the written complaint I submitted online. They just repeated the line I was given at the airport. Here's the relevant excerpt:
"Please allow us to explain that there aren't any oneworld Lounge or Malaysia Airlines Lounge at SGN airport. We do however have a third party lounge which the passenger must hold the Lounge voucher or you can purchase the lounge voucher from there. Lounge voucher was not issued here due to the ticket from SGN to KUL being on Economy class and the KUL to PER on Business class. "
And in case you are curious, the body of my reply!
"Thank you for your reply. However, although I comprehend your clarification, it remains unsatisfying.
Regardless of who operates the lounge, it is listed on the oneworld website as a lounge available for use by eligible oneworld customers.
In addition to that, the oneworld website clearly states the eligibility requirements for lounge access, not just in general,
but for this specific lounge, which I satisfied.
Finally, and obviously, Malaysia Airlines is a member of oneworld.
I paid to fly on a oneworld member airline and expected to receive the benefits clearly stated on their website.
Do you dispute that I satisfied the eligibility requirements as stated on the oneworld website? Your email does not say so, nor did any MH representatives at the time. Instead, they, and you, essentially just said they are not following oneworld rules.
Malaysia Airlines, in this instance, did not honour the terms of their membership within the oneworld alliance.
I was not asking for anything I was not entitled to. In the end, Malaysian Airlines has suffered a significant dent to the goodwill I held for them."
That was sent 10/7/19 (yesterday), no reply to that as yet.