amazonaws.com Chinese spam passes DKIM/DMARC

I’m getting a lot of spam from China via amazonaws.com.  It passes 
amazonaws.com’s DMARC/DKIM, so they’re authenticating it as legitimate.  
I keep reporting it to SpamCop, which says it’s reporting it to the 
originating site in China (good luck with that!), but SpamCop also says 
amazonaws.com doesn’t accept their reports.

1.  I’ve seen references to amazonaws.com as being widely abused.  Is 
reporting it to SpamCop generally effective, or a waste of time?

2.  What are the implications to legitimate email if I block 
amazonaws.com?  I do occasionally order stuff from Amazon, but their 
transaction-related email comes from domains like amazon.com, 
amazon.co.uk, and amazon.it.  However, I also get some legitimate 
notification email from vendors like Orbicule (Undercover) from that domain.

Thanks in advance for any insight.  Cheers,
—
Gib Henry