How are you accessing the email? With only the webmail UI and a browser? Or with a desktop client like Thunderbird? Or with an email app on a phone or tablet? Have you tried sending yourself a test email from some other account you have like Gmail or Mail.com, etc?
Similar problem with my wife's account. Using Chrome and the web interface she is not receiving any emails even test emails sent from my account. She can however send me an email which is sent and received in my account but if I reply she does not receive it.