I can send but can't receive, why?

Most likely your DNS is either not configured or needs some time for the settings to take. You received an email "[MXroute] Important Account Information" which tells you the DNS (MX) records you need to configure at your DNS provider. General rule of thumb is that it takes up to 48 hours for that change to go live, but 4-6 is more common (especially for TLDs like .com, .net, and .org).