Credit profile tarnished by OnAir

I purchased a contract of 2 years with on-air. I bought an explora decoder and I'm paying monthly using a debit order. Now they are tarnishing my credit score by implementing missed payments on my credit profile. My credit score is showing an amount of money that I don't even know about from on-air. This will negatively affect my credit profile if not corrected as soon as possible. I am very disappointed and will go far to see this crisis resolved soon.