not receiving email from b*****t@mrd-engineering.com

not receiving email from b*****t@mrd-engineering.com

not receiving email from b*****t@mrd-engineering.com while all other recipients (not on zoho) do receive the emails.
is mrd-engineering.com blocked? I believe it is a yahoo domain.

I have this domain and this email addressed whitelisted and have received their emails for years..the last email I received from this address was Friday 5/1/15 @ 11:56am central time. I have been informed email from this address  has been sent to me as recently as 5/4/15 approximately 8:00pm Central time. Several emails from this address have been sent to me between the dates/times above that have not been received.