Horrible Atlas

I have been contacting Atlas Finance for almost 5 months to pay off their loan without assistance. They don't want to provide me with their banking details or deduct money from my bank account, and it's negatively impacting my credit record! I have called their call centre (total waste of time), send them a message via facebook (the response said the matter will be escalated, 4 weeks later I'm still waiting), and even went to their branch (clueless about what to do) but I'm still not getting anywhere. I want to fix my credit score!