Lost emails

I have had several emails sent to me today with attachments starting about 9am this morning.  Not one of them has been received yet.

Because I work on my computer from home every day, I need reliable email.

Not sure what is going on.  But this is a recurring problem where emails will pop up days later after they were initially sent.

I am very frustrated.  I have closed my inbox to no avail.  Any suggestions?