PROMISED REFUND NOT RECEIVED

I HAVE BEEN WAITING FOR 8 DAYS AND AS TO DATE NEVER RECEIVED MY REFUND WHICH WAS PROMISED WITHIN 3 TO 5 DAYS, NOW THEY KEEP ON LYING, EVERY HOUR IT WILL BE IN MY BANK, BUT NOTHING! NIW I VANNOT HELP TO WONDER, WHO IS LYING THERE, ARE THEY EVEN TRUSTWORTHY?