Coroplast underbelly replacement

[parkerhw]

I have a 2017 Montana that I bought new. After a few months I notice something hanging down above the sewer drain. I crawled under my unit and discovered the coroplast had been cut and pulled down for some type repair. I don’t know if this was done at the dealership or factory. Who ever it was just tried taping it back. The tape will only last a shot time before giving way. Any ideas on how to fix this so it will last?