Okay, as soon as someone goes into their flyertalk, they can see - CLEARLY - that there is a message. It is even bolded!

Recently, I have been under the impression that my PMs don't even arrive at their destination! I ALWAYS ask for a read-receipt, and even though I see that the last time the person logged on was just 5 minutes ago, the PM that I sent yesterday STILL hasn't been read.

What to do?