Why do you think they black listed you ? If you get black listed then that nostr build is not censorship resistant .
But we need to host our data somewhere and big private cloud or server have TOS that man can not violate .
Discussion
The world is run by liars these days, so I get banned from places all the time as punishment for telling the truth too much
nostr.build treated me well so far before though, I think maybe they just messed up trying to set the free upload limit too high without being able to handle the storage + spam filtering difficulty