[2019] Ii have a bug or a glitch with my game I try to build something and the game keeps destroying it I have a video here to show it

Hey there @SOLID_ASSASSIN_97

We edited your original message with the link to the video.
Welcome to our community.
Pillars are known for not being particularly reliable when building on top of them with no additional reinforcement. Use foundations (as you found out) to increase stability and avoid possible issues like the one you reported.
Thanks for your feedback