Black tank bracket

[FFDADDY]

My rear black tank on my 2016 35c windsport has dropped down on one end do to the self tapping screws holding the bracket have stripped out. Has anyone had this problem and how did you repair it? When I looked at the top of the tank and then the plywood floor above the tank hole, I did not see any pipe that would extend into the tank. Should there be one. Thanks for your help.