Developer covered coal chute with drywall

We bought a townhouse from a developer and have had 99 problems so far. Everything from holes clear to the outside of the house to the latest…. The basement kept flooding and when we followed the leak we found that the coal chute was wide open behind the drywall. The air and water flow down the inside of the coal chute, freezing pipes, causing drafts in rooms immediately above, and is also full of debris (of waste water pipes, tupperware crates, old cables, you name it). During the walkthrough, the engineer report, etc, this was obscured by the drywall and is now just coming to light. The cover at the top is made of wood and is clearly inadequate. Can a case be made for fraud? It was intentionally hidden with the drywall and never disclosed. Is this common? And what’s the best way to fill it? Should we brick it from the inside? Cement it from the outside? How do we stop the leak?