Refund promised and overdue

I was promised a refund by RCS/Game for the credit balance on my account (which was approximately R900 at the time the email was sent) when following up I was then advised that this was a mistake by the agent. This is unacceptable and an expectation was created on a refund therefore I expect my refund. Game/RCS should write off these interest charges due to its agents error based on the written confirmation provided. I would like my refund as the call centre is giving me the run around. I escalated this to RCS AD383620 and was promised a investigation and call back and after a week no feedback again.