Useless customer service

Cellc has the worst customer service ever, I've been calling them for a paid up letter. Firstly the customer service call centers will take u pillar to post b4 thy transfer u to someone who can assist, when u finally get through to a consultant who is supposedly can help, they tell u that they have logged a case for you and promise to attend your case in 48 hours, they then take ur details saying they will send u a case number / reference number of which they don't send, and when you call again same thing no reference number to follow up cze it's never sent I'VE SETTLED MY ACCOUNT WHAT DOES IT TAKE TO GET A PAID UP LETTER