I CANT TRACK MY SHIPMENT! CHINA POST AIRMAIL ****HELP*****TRACKING NUMBER IS: RB509170694CN; RB509170694CN; RB509170694CN

ITS BEEN 5 DAYS SINCE THE SELLER HAS SENT ME THE TRACKING NUMBER AND I CANT TRACK MY SHIPMENT I HAVE TRIED TO SEARCH FROM DIFFRENT WEBSITES AND IT STILL CANT TRACK THE SELLER SAID I WILL REICIVE IT BY SEPTEMBER 11-23rd BUT HOW DOES HE KNOW THAT BECAUSE I CANT TRACK THE SHIPMENT???????? I NEED HELPPPPPPP??? PLEASE MY

PLEASE HELP ME!!!!