Blog rss feed stopped working

Hello there

My WordPress rss blog feed seems suddenly not to be working. It’s returning a 404 error.

http://www.clevercarbuyer.com/blog/?feed=rss2

This blog url does still work:

http://www.clevercarbuyer.com/blog/

but nothing from the rss feed does, such as facebook/networkedblogs

I asked my ISP support and they said this:

“There doesn’t appear to be any rewrite rules in the .htaccess file. They may be required to get the feed URL working.
I’m not sure what they should be but support from WordPress should put you in the right direction.”

Are you able to shed any light or point me in the right direction please?

Thanks a lot.

best
Mark