Redirect to Facebook Messenger with an attached msg?

I don’t know if this is the appropiate place to ask this kind of question

As you may know when you manage a facebook page, people can msg and u can answer them, but you can’t msg them if they don’t msg you at first, this means you can’t start a conversation with a follower from your fanpage.
In my drupal website I manage a form that people fill with specific information, one of the information fields is their facebook profile url, so I can msg them, but then I released I couldn’t msg them (at least not through my fan page, but throught my
personal profile which basically IS NOT THE IDEA), and that’s a facebook configuration that I can’t change.
I need to contact people through my fan page, for this I need they msg me first so I can talk to them later:

  1. A fast solution is to set a msg with a caption “SEND ME A MSG “after they submit the form, using RULES MODULE, but this is not a good solution, people could msg or not.
  2. Second solution was to redirect them (with RULES again) to this url: … after submitting the user is redirected to that page where “yourfacebook” is the name of my fan page, and it redirect automatically to a conversation with me on computer, and opens a conversation to me with messenger in cellphone (if messenger installed), [this solution is not bad at all, cause automatically opens for the user that is logged in at that moment and I assume that user is the same that is submitting the info.] but again this solution is not the best, cause even I display a direct way to send an inbox, user could just close and no info will be sent.

So I dont know is this is possible throught a PHP code in RULES but what I want is after submit the form, redirect page to a messenger link, but this messenger window will also send automatically a msg… if this not possible through drupal, maybe just to write the msg on text field of messenger so user just click the send button…. some help?

Drupal version: