Use of low quality wood, tiles and plumbing products.

Q: Casa Grande is a developing Builder in Chennai. We have brought a villa of Casa Grande Urbano at Ponmar recently. But we are completely worn out by the quality provided. They attract consumers by attractive words and budget. But everyone have been charged 10% of the total cost during handling over with fake reasons. All the customers are highly dissatisfied by the quality provided. we are forced to pay extra amount at last minute. Most of homes are leaking during rain (Rainfall inside home) and doors got broken even before handling over. But, they are not caring our concerns. They have not used the material provided in agreement and have used low quality wood, tiles and plumbing products. Walls of all the homes have been cracked out. Please suggest the remedy.