Useless service

I rented a car through Planet 42 and my account was paid in full with a letter from them confirming that. I tried in vein getting hold of them, not answering their emails or WhatsApp. They stopped the debit order but their deductions are still showing on my profile with the credit bureau and it shows that I am not paying. Thus is effecting my credit score, this after the fact that my account is paid up and I have a letter from Planet 42 confirming my account paid up. I will now be seeking legal advice to solve this matter.