I have followed http://en.blog.wordpress.com/ successfully for about 20 months. Since Sep 7th email notifications have not been reaching me regularly. I did get the last one and the third to last one however. I do not have spam filtering installed.
I read through the blog a couple of days ago and sent myself an emailed copy of the ones I missed. These did not make it either. Nor did they appear in my ISP's webmail like other mail does. However I managed to successfully send a copy this way to my husband at work.
My ISP insists I check with you before they will do anything, to look into it. "They want a copy of the bounce email!!!!" I find this unreasonable, but have contacted you for comment as requested. I have also set up email notifications for another blog I follow to see what happens there.
Blog url: http://theafi.wordpress.com/