account closure not done

I paid up the account and filled in the form for account closure in 2014 at canal walk, the lady there said they sent the form and that it will be closed. I found out yesterday that it was not closed and still reflects as open in credit bureau. I sent the email and spoke to the lady at tygervalley store to request proof that the account is closed as it is requested by the bank, I still have not received anything in writing stating that the account was closed more than a year ago!