No resolution to a simple update request

I have more than a year ago had my name changed and needed to update details with Nedbank. I went into Fourways, handed in all relevant documents & had details updated across my various accounts. Then I find out the name change was implemented on every account except my Just Save investment. I phoned in & was assured this was corrected. I stopped receiving statements for a while & then a few months ago starting receiving them again only to find that the details are still incorrect on that particular account. I call the call centre a few times-wait on line forever only to be told I need to go into the branch. I call the branch & they tell me I need to call the call centre. Are employees actually aware of who does what? I call again & again only to either wait on hold & eventually have my call cut off, or to be told that all consultants are busy & someone will call me back. My last call was a week ago & I'm still waiting for someone to return my call. Is this what you call customer service? How damn difficult is it to change one small detail on one account when all others have been updated with the correct details? Can someone competent please call me so this can be resolved.