my 3 hours shield had never work

hello everyone
i took a 3 hours shield to protect my rank in the divine championship and it never works.
i was 3rd with 700 points and now i lost 120 point down to 580 at the 6th place.
i sent 3 mails to the support and i don't have any answer.

what could i do please?
sorry for my english i am french