I can't say why YouTube might be deleting your videos, but here are
some thoughts:
1. If you do upload anything containing anything you didn't create
yourself (music, video, sound effects, photographs, live concert
footage), you must have the express permission of the copyright owner
before you upload.
2. YouTube prohibits certain types of commercial use. If a video is
primarily geared towards promoting a product or a service, it's likely
to fall foul of this rule.