There are lots of urls are showing in Google webmaster tools whose are giving error in crawling. My website url is https://www.carbike360.com. It has more than 1 Lac urls, but only 50k pages are indexed and more than 20k pages are giving crawling error.

I am also working on an e-commerce website whose spam score is 8. The domain is Carbike360.com. I want to reduce this, but I have not got any solution. I have also checked quality of my backlinks but those links are fine..
Will anybody help me to decrease the spam score?