Everything is replaceable. Only a question of time and money. Any RV shop will be able to sell you the flanges. They may have to order as doubt that they sell many. Hopefully you only screwed up one side. That one will require cutting the pvc pipe, maybe adding a short section of pvc and cementing everything back together. Gray willl be a lot easier to work with than the black so in that regard you’re lucky. With what’s happened so far, might look at finding a plumber or someone familiar with working with PVC.
2006 Gulf Stream Friendship G7
350 Cat, Crusier Lift w/ Honda VTX
Blue Ox and 2019 Chevy Blazer RS AWD V6