Some ISPs will employ filters and/or blacklists to protect customers from unsolicited emails. Most users with this problem will stop receiving order invoices or notifications from BrickLink but will still receive other emails. To remedy this, we're working on getting on a global whitelist that will prevent our emails being blocked or sent to spam folders.
In the meantime, please check your spam or junk folders to make sure our emails haven't been sent there by mistake. You can also visit your Junk Email Settings and add us to your safe senders list (email@example.com). This usually will fix the problem.
If you still aren't receiving our emails, please contact your internet service provider directly via email or phone. You can request that BrickLink emails are not filtered as you require constant contact with your buyers and their filters are interfering with your business.