Update Changed URL but keep cache invalid content

Hi,

Due to I created my FAQ page with original name “frequently-ask-questions”, so URL was http://www.trucking2u.com/frequently-ask-questions. Then, I changed it to http://www.trucking2u.com/faq
It was nice, but maybe I once created FAQ with some plugin, created same URL (www.trucking2u.com/faq)
And now, I deleted all the unwanted FAQ plugin and keep only the one I want (acronix faq)

My problem is if I go to URL : http://www.trucking2u.com/faq , it keep show ‘deleted’ page. If I change the page URL to different , ex: http://www.trucking2u.com/faqq , then it is OK. How can I solve this? Thanks in advance.