4 times i vote on Community's Choice but did not get any single trading card

You must be lvl 8 to get anything.

.."If you reach Steam level 8 during the sale you'll be given all of the cards you've missed."

It seems you don't pay attention to the details. You are only level 7 and you need to be at least level 8 this time around.

CS:GO is the cheapest badge to craft btw. You can get the 5 cards for about $0.25 to $0.30 and it will get you to level 8. The sale event cards are usually granted retroactively so once you make level 8 you should get the cards you 'missed' as long as your votes were recorded.