Kulula refund soooo long overdue

I booked a ticket on 17 January 2019. I realized that I was overcharged and contacted the call center on which the agent confirmed it was due to a system "glitch" and that it happened to a few clients that day. She took all my details, did a dummy booking and confirmed I was overcharged and that I would be refunded. I contacted the call center 2 weeks later and another agent confirmed that no request for refund was done and that it will take up to 8 weeks for the refund to reflect in my account. Last week I was told to be patient as it was only week 7......seriously. It is now week 11 and still no refund to my account. I understand if I cancelled my flight that I would have to wait for 8 weeks for a refund but the refund due to me is due to Kulula overcharging me. I'm extremely annoyed by this and guess that I'll have to make my 5th call to them to speak to another agent, explain the whole situation again and still have no refund.