Hey, I'm sorry about that. Have you tried clearing the cache on your system and restarting your game?
If you need assistance with clearing the cache you can head here for guidance: https://support.activision.com/articles/en_US/FAQ/Deleting-Old-Files-from-PlayStation-4-and-Xbox-One...
If your level is still stuck the best suggestion would be to grab a screenshot of the issue and report it over to official support. They will be able to gather more information and assist further as soon as possible:
Contact Us (Live Chat):https://support.activision.com/contact_us
Twitter Assistance: https://twitter.com/ATVIAssist
Facebook Assistance: https://www.facebook.com/ActivisionAssist?fref=ts
The live chat hours with an Activision agent on the contact us page are from 11a.m. - 7p.m. Pacific Standard Time