Cracked and uneven floor - NHBC claim

[griellwe]

Hi, I recently made a claim to NHBC. I bought a house last year (7 years old). When I started decorating the ground floor I noticed that there is a big crack comming from living room to a dinning room - about 5 m long. Also small area of floor near to the garden doors is completely cracked and needs to be digged out (about 2 square metres). All floor is covered in few very small cracks. I also noticed, when I moved a sofa, that the floor is very uneven and there is a slope next to the wall - floor near to one wall is 2.5 cm higher than floor on opposite wall (room is 3.5 metres wide).
An inspector from NHBC came to view the house, said this is not a structural problem and the floor was not probably done properly by the builders in the first place. I pointed all the cracks and that floor is going up by 2.5 cm but he said NHBC cannot do anything about it. He took some photos and I am waiting for a letter from him with final decision but as he said there is nothing they can do about it.
What do you think about it? Should it be repaired by NHBC?

Thank you