I had no issues with Google's mail servers, however, Microsoft's let a few of my mails just vanish. They were accepted with a 200 OK but didn't even go into the

I had no issues with Google's mail servers, however, Microsoft's let a few of my mails just vanish. They were accepted with a 200 OK but didn't even go into the spam folder. Granted, I'm using an .xyz domain, but still, I think this is hostile behavior. Another fun story, I once tried to contact a public authority and my mail was rejected. I then tried to contact the postmaster inbox, same thing. I had to use my gmail account and was initially met with a dismissive reply. Only after asking what the job of the postmaster incorporates if not helping users with delivery issues and whom else to contact I got helped reluctantly.