MTN store always offline

MY PHONE WAS ****** ND I WANTED TO DO A SOM SWAP AT THE STORE BECAUSE I TRIED DIALING 135 TO DO IT BUT SOMWHOW IT WAS UNSUCCESSFUL.WHEN I GOT TO MTN THEY WERE OFFLINE THE FIRST DAY .I CAME BACK ON ANOTHER DAY ..STILL OF LINE.. I HAVE BEEN USING MY NUMBER OVER TEN YEARS NOW .. I DONKT KNOW WHY WE HAVE TO BEG FOR SERVICE TO BE RENDED.I AM STILL UNABLE TO GET HELP.. I USE TO WORK FOR MTN AND WE NEVER HAD SUXH ISSUES .. I AM VERY DISAPPONTED AND I NEED MY NUMBER.