PAID UP ACCOUNT NOT CLOSED AND UPDATED ON MY CREDIT PROFILE!!!

I have settled my account with Mix Telematics this month. To my surprise I received an sms that I was still owing the same amount I had settled. I called in to report this and the consultant advised it was an error. I further requested a paid up letter and my information to be updated on my credit profile. I have not received any paid up letter and my information is still not updated on my credit profile, it still shows that I owe the amount I have settled. I need this updated ASAP and proof that it has been updated. I also need a paid up letter. I want this account closed immediately