FYI, you are not addressing Apple and this is not Apple support. We are all volunteer users so we are not expected to be "taking responsibilities". And, just as an aside, the App store is just a store - there is no way that Apple can be responsible for millions of apps on millions of differently configured devices. That is utopian. Here are Apple's terms:
Legal - Apple Media Services - Apple
which include:
The App Provider of any Third Party App is solely responsible for its content, warranties, and claims that you may have related to the Third Party App.
Apple is responsible for providing maintenance and support for Apple Apps only, or as required under applicable law. App Providers are responsible for providing maintenance and support for Third Party Apps.
And, it is certainly not anyone's fault here that Facebook's support is not responsive. Contact Mark Zuckerberg (CEO of what used to be Facebook).