Paid letter and poor service

I really don't understand what I have done to Cell C to deserve such poor service. I have settled my account in September already but still no paid up letter. A lady called me after I posted my review on hello Peter and she said she will get back to me, but as usual she never did. I have sent everything to them including proof of payment but still nothing has been done. Now my life has to stop just because someone is not doing his job. I can't apply for any job because of my credit profile. All I want is my name to be cleared, I am tired of calling and emailing you everytime. You are disrespecting your customers How do I refer my friends and family to a company like this. Please the next call I get must be about receiving my paid up letter. I have more than 10 ticket numbers from you and not even one person called or gave me a feedback. Your supervisors are useless all they know is to tell you we will escalate.