Credit due to me unpaid after a week

On February 2015, I cancelled my contract with the company. Last month I received an invoice stating that I am owed money from Cell C. On 5 May 2015, I called the customer care centre to clarify when I would be reimbursed the money? From which a case was opened by the Retentions team, for the Billing team to deposit the money into my account within 2 days. It's now 14 May 2015 and no one from the Billing team has contacted me regarding my money and, when I followed up on the 11 May 2015 with Customer Care: I was informed that for an unknown reason, the Billing team was deliberately delaying in releasing the request for my funds to be deposited. Can I get clarity as to when my money will be paid to me?