Some mail messages come in but others do not

Some mail messages come in but others do not

I have just started trying to use Zoho and am clueless as to what I am doing...  I had hired someone to create a web site for me and, as part of that, he was supposed to set up Zoho for my email (this is a small business).  I wanted it to be a POP3 account, but he set it up as IMAP because HE thought it should be that way.  When I asked him to change it to POP3, he quit!

I have now changed it to POP3 myself (at least, I think I did) but it doesn't seem to be working properly and I'm not sure what to do.  My domain is hosted by GoDaddy.  All the emails successfully go there.  However, a few will also come to Zoho and the rest don't.

I don't understand what is happening.  Help?  I can't fully switch over to Zoho until this is fixed...  Also, I set up several email addresses under this account but I don't know how to access them.  I only seem to be able to access the first one.

I'M SO LOST!  Thanks for any help you can give.