cache dont realy work

hi
we buy the premium total cache so maybe it will help for our woocommerce website caching.
but it looks like it saves only cache for pages i visit in my browser
but when i close the browser and try again it looks like it loads once again the regular page and not the cached version and every user goes in gets the regular page from quests from the DB and not the cached version?

also looks like the cache preload not working
it should run all the pages and save for them a cached version
and always the site falls down because lots of DB requests

is there any way you can help us please ? this is very frustrating