I am Having a Problem...

As I have checked my blog reader feed today I have been bombarded with spam in the reader feed. I check it and there are 10 different entries for things for sale, fashion jewelry, tennis shoes, etc. when I start searching where they are coming from and return to the feed to try and eliminate them they are not there anymore. The blog they originate from isn't even on my blog list, so I can't unfollow. I have checked Help for a solution, but Blogger "help" really isn't very helpful. Is anyone else having this problem?