@yoster - Thank you very much for this detailed message here, Yoster.
Given that you've tried many things now and have advised about the change of service, can you please raise an In-App case or raise this with our Facebook or Twitter teams? We can grab some details and have it raised for you.
Did we answer your question? Please mark it as a Accepted Solution and if you see something that was helpful to you or the rest of the community, giving a Kudos is only a click away.