We never delete comments outright unless the author asks us to*, and even in that case you would have seen [deleted], not a blank page. If you saw a blank page, then there was a bug, either at your end or ours.
Your posts are autokilled because your account is banned. Your account was banned by a software filter that categorized it as a troll account. Either you've had many accounts that have been banned in the past for breaking HN's guidelines, or there is a bug in our software.
When an account has an established history on HN, we tell people we're banning them and why. But when a user responds to that by creating an entire series of accounts and continuing to break HN's rules, eventually we start shadowbanning them.
* There have been a handful of exceptions for legal reasons over the years, perhaps half a dozen or so.