How to contact someone who is not in your friend list on Facebook?

[Rerore]

I need to contact someone I know but not in my friend list. As I know, in this case, when I send a message, he/she can't receive it as a regular message with a notification, instead it goes to the "other" box that gives no notification. So he/she can't notice or notice a long time later.

Is there anything to do when this happens? Sending the same message more than once can change it?
@ Miranda : Thanks for your answer, but I still have an other box although i am on timeline. ???

@ Ironclad : Thanks for your anser. When I go the timeline, at the top right, there is already a "send message" button next to the gear icon. I can send a message, but he/she can't see it since we are not friends, I guess.


May this problem be about using facebook on mobile phone?