Can you check out your SmarterTrack logs to see if there's any helpful information on why tickets stopped importing? To view these, log in as an Administrator and click on Settings. Expand the System Settings folder and click Log Settings in the navigation pane. Click the View tab to read your logs. You can find more information on these settings here: Log Settings
If this doesn't help point you in the right direction, I'd recommend getting in touch with our support department. Taking a look at your account, I see that you have an available support ticket that can be used for this. Keep in mind, if the issue is determined to be caused by a bug in the software, your ticket will be refunded back to your account for future use. To submit a ticket to support for direct troubleshooting, please click on the Tickets tab at the top of this page, make sure you're logged in, and click Start Ticket.
Hope this helps!