MTN says i owe them

<p>Took a contract with MTN in 2009, renewd it in 2011 but never renewed it again. A few months ago I got a call from Shapiron Shaik Defries and Associates saying my MTN account is in arrears. Asked how it that possible as MTN was debit the money straight from my account they coundn't answer me, asked them to tell me which month i skipped again they couldn't answer me. I need an explanation!</p>