I had the exact same experience. I shoot weddings for a living and after having 2 strikes with the threat of having everything removed upon the 3rd strike, I opted to go into 2018 uploading everything to YouTube instead. About 2 months ago, I received my 3rd strike on a video I had uploaded 4 years ago and my whole video archive was deleted. I still had to re-upload previous 2017 and 2016 projects to YouTube, but at least all my 2018 files were already safe. I'm just bummed I've put money into Vimeo and they wrecked my shit.
Edit: All that to say, heed Andrew's warning, because it can and will happen. It's just a matter of time.