Tiles defects (broken tiles from underground issue)

I am staying at one of the Terra Nova developments called ‘’ The hills Estates” in Trichard which I bought the house in January 2021 and am staying alone, few weeks ago when I woke up one Sunday as I was making the bed I noticed a swelling on the tiles as if there is something under ground that I am not sure what it is as the area where the houses are built is a farming area and am not sure if a proper analysis underground was done. I reported it and after numerous times of following up, one guy was sent and he checked and said they would comeback to fix the affected tiles and never came back. After following up more than 5 times again I was sent an email that stipulates that an investigation was done and the defect fault is not related to them. I am not sure what investigation was done as I don’t understand what is the reason behind the swelling of the under the surface that is affecting the tiles considering the affected area next to the window that I don’t normally use. I opted to buy a brand new house since I was avoiding fixing old house defects, but a brand new one with just 3 years has defects from poor workmanship and design defect as the area was supposed to have been checked underground and addressed. I am only told about the “retention period that has expired” though we both know the reason and now I must be liable for their poor work.