Wow, really?! I started using DTube just a couple of months ago so I have no experience with it but I didn´t know they delete all content. Hopefully, you have copies of all the videos stored somewhere...
Did you check the oldest of your DTube videos? I think normally after a few months they start disappearing.
Yes, I have copies from most of these videos, uploaded them to Bit.Tube and then inserted the link to these Bit.Tube videos to my STEEM posts with the deleted DTube videos.
The oldest I could find was 5 months old and it is still there but it doesn´t play when I click on it... Thanks for the heads-up man, I had no idea...