paneling used under home?

[KEN]

I DON'T UNDERSTAND HOW THE BOTTOME OF OUR DOUBLE WIDE HOME IS CONSTRUCTED OR SUPPOSE TO BE, BUT AFTER TRYING TO KEEP THE INSULATION, AND THE BLACK TYPE PAPER UP WITH DUCT TAPE WHICH KEEPS COMING LOOSE DUE TO THE MOISTURE UNDER OUR HOME, THE MANUF. CAME IN AND PUT A PIECE OF CHEAP, CHEAP, WALL PANELING OVER THE INSULATION, THEN COVERED IT WITH THE BLACK PAPER AND SAID THAT IS ALL THEY COULD DO. THEY STATED THE OTHER WAY WAS MORE EXPENSIVE AND THIS PANELING IS WHAT THE SERVICE MGR. GAVE THEM TO USE. MY QUESTION IS : SHOULDN'T THERE BE PLYWOOD OR SOMETHING MORE SUBSTANTIAL? WON'T THAT MOLD OR WARP IN TIME?
THEY ALSO PUT IN MANY SCREW HOLES AND DIDN'T HIT ANYTHING SO REMOVED THEM AND COVERED THEM WITH DUCT TAPE. I'M WORRIED ABOUT MICE, ETC., SORRY I AM SO DUMB ON THIS MATTER UNDER OUR HOME, THANKS FOR ANY ADVISE.....