Please help.

I have just had new turf laid and it is a mess. The grass looks dreadful. It is bumpy, patchy and very uneven in terms of the strips laid. It even looks like the guy filled in small patches with bits of turf. It has not been straightened off at the edges either.

I have stupidly paid for this already and am now left to sort it out. I am very upset. What can I do to help this grass?