If you have not received a certain email you can follow these steps:

1. Make sure the sender has not been blacklisted world-wide for Spam issues. If this is the case the sender would have received a bounced-back message with instructions on what to do.

2. Make sure you have not exceeded your mail quota.

If you are using cPanel, log in to cPanel, go to Email accounts and check  your mail quota;

3. Make sure your MX records are correct.

If you are a SiteGround customer and your issue persists even after following the above steps, please post a support ticket from your Help Desk > Email related problems. Our support team will do their best to assist you and resolve your issue.