New Construction Plumbing Issue

[Sophia Liu]

Hi all, I am new in investing and took a safety bet to buy a new construction but now it turned out to be a disaster. I really need some help!

I just purchased a new construction this year in June and has rented out since late July. Recently there was a plumbing issue and the water back up from the toilette which caused a large area on the second floor wet even dripping to the first floor. The renters declared that they had never put anything inappropriate to the toilette and had heard goggles in the toilette since they moved in. The builder (Lennar) helped with the plumbing and claimed that there were no construction debris issues and it was the residence' fault which is not under warranty. They plan to charge me for all the repairs. No one has evidence of what really happened but the plumber claimed that there was no debris issues. What should I do? This house has caused a lot of headache for me since rented. The dishwasher, the electricity did not work at the beginning (although shown in the inspection report)... Please help!