How do I stop receiving emails from 'lowermybill.cu.cc'

How do I stop receiving emails from 'lowermybill.cu.cc'

I am getting many spam emails from this company and I cannot get them to stop. Hitting unsubscribe made it WORSE. I have black listed the above, but they still keep coming through as every domain is different.

Here are some of the senders just from today:
How do I get this to stop? Just marking as spam doesn't work.

Thanks!