Facebook chat message delete

I am desperate to have some messages ( which are unread) that I sent to a non friend on Facebook either deleted or marked as "spam or abuse" so they can not be read. The messages would be in his "others" section in the inbox.
Following advice I have sent 8 or 9 fake abusive messages to some friends so they could report them as "spam or abuse" in an endeavour to have all of my messages marked as "spam or abuse"by Facebook. this was three days ago and I have had no result whatsoever. I used the F word a lot in all the messages, but maybe I need to send more messages or a different type of message.Please help