Yep, they only recognize Quest serials, womp womp(I have a Rift S, been there). You can get around this by framing your request for support in a different manner, just say you're having a problem with an app or request a refund for something or any one of the non-rift specific means of getting them on the horn that doesn't require the input of a serial number. I could be more specific and tell you the many ways I've had to do this in the past, but thankfully it's been so long that I can't remember exactly which methods were 100% successful every time.
Imo, it's not necessarily a bad thing that you aren't able to contact meta support, I can say with honesty that they never, not even one time were able to solve a single one of my problems, and they handled each issue in the worst possible way each time. I once had a ticket open for over a year which ended with no resolution, the entire time they doggedly attempted to close the ticket and would have done so had I not maintained a vigilant eye on my email inbox for their "do you still need assistance?" messages. If you do have the unfortunate experience of having to speak with these support agents, just remember, if they don't ask you for the logs, they do not actually intend to help you, trust me on this. The logs contain everything you need to know about why this failed or that is broken, the logs log literally everything on your computer, and yes, they contain private information, so make sure that they only get sent to only where they absolutely must be sent in order to resolve the issues you're having. Either to Meta directly via their support file share protocol(which will probably be too small(50mb, I believe) for you to include all of the logs, which means you'll have to create a custom zipfile of only the logs you believe to contain the most relevant information, this is Meta in a nutshell), or to someone you know who is very, very computer savvy that you trust implicitly, and in that case, I'd recommend you still peruse the logs(which will be a good thing for your understanding of them anyway) and redact any information that you perhaps wouldn't want to risk becoming public knowledge for whatever reason.
