Not receiving emails from some people

I'm not receiving any emails from some senders.

There is nobody on my blocked list and the emails are not going to my junk folder.

It seems as though people are telling me that they have emailed me, but I have received nothing.  I am forwarding my emails from one account to my Hotmail account.  I have checked with my web/email host provider and they have confirmed I have received the "missing" emails into my original account, and that it must be a Hotmail issue. 

 I have noticed, that if the person phones me and says they have emailed me (and I have not received it) I email them and then when they reply to my email it works, I receive their email.  Further, once I have received someone's email, I have no problem receiving future emails. 

So what I think is happening is that when unknown email addresses email my original email account, somewhere in the process of having that email forwarded to my Hotmail account - Hotmail seems to be filtering these emails and I am not receiving them.  I have checked my junk email, and I still get junk.  Also, my original email account deletes the forwarded email, so I have no history of the emails I am not receiving, which is problematic. 

If you need more information from me in order to help, just ask please.

Any suggestions, any help would be much appreciated.