19 Months Paid Off Yet still not updated

The level of service this company provides is ridiculous. I had an account which was handled by them, paid it off last year August already. They provided me a Paid Up letter yet the account still appears as opened and in arrears for 19Mnths on my ITC report.😡 I have contacted the numerous times and been sent pillar to post. I need this to be sorted out urgently as it has caused me soooo much inconvenience in persuading other ventures.