Facebook filters messages to keep you from getting spammed. This is mostly a very helpful tool, but occasionally real messages, business opportunities etc. get filtered because someone is in no way connected to you and trying to reach out.
Not all of Facebook's attempts to diversify, or "unbundle," have been successful, however. Facebook discontinued its Snapchat
Of course, there are some easy things you can do to avoid the forced switch. For one, you could quit Facebook. Or, you could
How much access to your (and your friends') personal data are you prepared to share for access to free mobile apps? I suspect the amount is significantly less than that which you actually agreed to share when blindly accepting the Terms of Service.
There are, however, several features that are noticeably (in some cases inconceivably) missing that make Facebook Messenger