Overdue Refund

I don't know what one must do to get service and find honest responses and client liaising officers. I've been waiting to receive my refund since August 2018 to date. I was told I'll receive the refund within 90 days, but to date I'm being sent to pillar to post. Having to get progress and finality on my issue has been one struggle that I seem not to win. I've tried to be understanding, being told about moving offices. I'm always given the same story of referring the issue to top management and I'd be called before end of the day, but till this day nothing. I really need the refund and they are a huge disappointment.