All emails going into the same account

I have created and email account for B...@brentreid.com and another one for J...@brentreid.com. But emails for B... are going into J... mail box. Also emails FROM J.... appear to be coming from B...

Not sure if this is related but:

B... doesn't actually have a Zoho account -- just B...@brentreid.com -- does he need a Zoho one?
The brentreid.com registrar has pointed the MX to mx.zohomail.com -- not in the normal way but not to a specific address, so that's not the cause.
B also doesn't show up as a user in the Zoho account but he does have an email account? Is this correct?

Thanks in advance