Paid up phone contract but Still debitting account

<p> </p> <p>I had a cell phone contract with Virgin Mobile which I then had problems paying, to which they then handed my account over to Lawyers. </p> <p> </p> <p>I managed to pay off the account to the Lawyers in 2013.</p> <p> </p> <p>i just recently got contacted by another company contracted by Virgin Mobile to do Debt controlling. When I told them my account was paid in 2013 , they wanted proof of my payments to which I dont have anymore.</p> <p> </p> <p>I need Virgin Mobile to liaise with the law company they had contracted for me to make the payments to. </p> <p>Ive tried different ways to resolve this to no avail.</p> <p> </p> <p> </p>