I can't tell if the rust colored flight feathers are white or if the sunlight is making them look white. If his flight feathers were white then he would at least be split to white or pied.
What you are seeing is the normal look for a young peacock. A peachick can't just go from brown to blue in a day and so they go through a process of steadily gaining colored feathers. This young peacock just hasn't gotten all of his blue/green chest feathers yet! If this seller raises peafowl they must have not seen an India blue peacock grow up before.
So here is a close-up of a young India Blue peacock's chest.
Here is a close-up of a mature India Blue peacock's chest.
Buying birds "split to" and hoping th actual "split" mutation happens with a peachick showing the mutation is like hoping to win the mega millions lottery drawing.