Well there's a bit more aggression here than I thought this warranted.
It's possible that the pictures could just be really poorly lit or low quality and we just can't see the color and blushing that would really make this snake look like a pastel. It's also possible you just have a normal with an interesting pattern that someone without much experience saw and falsely labeled a pastel. It happens, and at best you could take it back and say you want a different snake, but if it's only a pet then it doesn't matter, does it?