Sorry about the trouble. In addition to the suggestion shared by @Monika Gause, you can also install the Pantone Connect Plugin (https://exchange.adobe.com/creativecloud.details.103029.html) to find the missing Pantone colors. After installing the plugin, reopen Illustrator, go to Windows in the menu > Extension > Pantone Connect > Search for the Color.
Let us know if you need any further assistance. We'd be happy to help.
It looks like this functionality in Pantone Connect is no longer part of the free service. Are there any plans by Adobe to include the rest of the recently added Pantone swatches?