Paid up account in arrears

i once made a mistake of taking a loan with Getbucks and i paid up my account in 2013 but now i cant qualify for credit because it shows i am in arreas on my Getbucks account. ive sent a bunch of emails for a month now to both Collectetions and Charlize but no response. i wasted lots of air time calling their collections department and nobody answears. the voice prompt keep telling i am caller number one tyhe next thing i am caller number 4. the worst service iv ever recived in my life and i even regret why i took a loan with them in the first place