EXTREMELY BAD SERVICE

I have been incontact with FNB regarding my premier account that I have been trying to close for the past 3months now , this account is not being used is always overdrawn , in February I had to pay almost R2500 after paying i went to the bank in Kempton park to request for a downgrade to a cheaper savings account this could not be done on the day as i was told that the particular office was not open even though it was a Saturday, i then phoned requesting for the same downgrade to a gold or easy plan account still this could not happen , month end of March i had to pay R456.00 because it was still not fixed and was overdrawn , i paid this balance and immediately i contacted the call center again and was promised that this would be sorted and it was not sorted . I then decided to log a complaint ref number *** and i was promised that someone was going to sort it out ( the amount overdrawn was cleared and the consultant promised me that someone else was to call me to do the downgrade this never happen .. I HAVE BEEN PHONING STILL THIS HAS NOT BEEN SORTED LAST WEEK I PHONED A CONSULTANT PROMISED ME THAT SHE WAS PUTTING ME THROUGH PRIVATE BANKING TEAM AND I LOST HER WHILE I WAS STILL HOLDING SHE CALLED ME BACK AND ATTEMPTED TO PUT THROUGH AGAIN ALL TO NO AVAIL ,I HAVE BEEN RECIEVING SMS EVERY WEEK ABOUT MY ACCOUNT BEING OVERDRAWN WHICH I DONT UNDERSTAND, ALL I WANT IS FOR THIS ACCOUNT TO BE CLOSED AND I WANT NOTHING TO DO WITH FNB AGAIN