Facebook glitch or something

So months ago I notice my Facebook was acting weird ** Any time a friend sends me a message on Facebook, I try to open it and it directs me to my safari Facebook which I didn’t find annoying at some point but it actually did. Now to make matters worst the messages directs me to APP STORE TO DOWNLOAD THE MESSENGER APP I ALREADY HAD FOR YEARS. and I have contacted Facebook for help no reply and nothing was done and still months months later it’s still the same and getting worst ????

Bdutj about Facebook, v163.0