Autopage - billing On a closed acc

I had a autopage celluar contract about 4 years ago which was cancelled in 2012. The account was fully paid when cancelled. 4 years later i app**** for vehicle finance which was declined due to the autopage cellular account being arrears, i find this unbelievable because i was bever notified of any outstanding amount since contract was cancelled. This has impacted my credit rating due to incompetance from autopage, i need this resolved or i am logging the next complaint with the Ombudsman.