I'll be blunt here. Blogspot / Blogger hosts millions of blogs, and has millions of worldwide customers. You send in a complaint to Blogger Support, about your blog, and it goes into a long queue. And if it's just YOUR problem with YOUR blog, that's where it will likely stay. Problems affecting multiple blogs, and problems affecting multiple Bloggers, or customers, get higher priority. That's common sense.
So, if YOU notice a problem with YOUR blog, it's up to YOU to troubleshoot. Now, I'm a desktop support technician, and I preach diagnostic procedure. Constantly.
Note: This article started out when the 450 error became a problem, and it's now a part of my general tutorial on troubleshooting Blogger problems.
If you're having a problem, don't just drop it on Blogger Support. Involve Blogger Forum and Google Blogger Help, too. Update all 3 groups, regularly, when suggestions are made by any others. Be patient and persistent.