I had the experience that some private messages disappeared, the people i send those never got them. It happend more than once where i am sure about it. Maybe i

I had the experience that some private messages disappeared, the people i send those never got them. It happend more than once where i am sure about it. Maybe i did something wrong but there is no way to find out. Since then i never send important messages any more over facebook. There is no way you can be sure they got the messages or can find out why they don't got them. E-Mail feels less like a black box.