WP fastest cache for logged in users

Hello i use WP fastest cache in a B2B shop, in which prices appear after customers login.
While im happy with its caching performance, while i have checked the box “no cache for logged in users’ customers are logging in and still see the shop with out prices. They see the cached version of the site again. Can you help with this issue so it doesnt not happen again?
Is there any snippet to force clear cache after customer login?
Thanks in advance