Phone returned within 14 days, but never received

KPN, I ordered a refurb phone from you guys that i didn’t like. So within 14 days i sent it back with the return label in the box. How did you not receive it? I don’t know. Anyway, 6 months later you finally took the hint, that i want to cancel my contract. But you didn’t let me keep my number, annoyingly, I’m with another provider now. But you still decide to bill me more than 1000 euros for the phone i never used and i sent back in April, ridiculous. 

The worst thing is that you try to damage my BKR record because I refuse to pay you for a phone I don’t have. Your customer service team don’t do anything to help, because they can’t, it’s not their job. Nobody is responsible but the customer, apparently.