COMPLAINING ABOUT BAD SERVICE

I AM VERY SCHOCKED AND DISSAPOINTED WITH THE SERVICE I GOT FROM NATIS. I PAID MY VEHICLE LICENCE A OVER A WEEK AGO AND I DID RECEIVE ANY EMAIL FROM THEM , WHEN I GO TO THEIR WEBSITE TO CHECK MY STATUS IT ONLY GIVES ME A REFERENCE NUMBER WITH A BLANK RECEIPT. I TRIED TO CALL THEM SO MANY TIMES AND EVERYTIME IM CALLER NUMBER TWO THEY HANG UP THE CALL. I NEED THE VEHICLE LICENCE URGENTLY. SHOULD MY COMPLAIN BE TAKEN SERIOUS AND INTO CONSIDERATION LET THEM PLEASE CONTACT ME ON *** OR ***