Really poor customer service

I've been calling the call centre since the end of June. Been given 5 different Reference Numbers and each time I'm being told that I will receive my refund within 21 days or someone will call me back yet I never get called back. When I decided to call the complaints line, I get transferred back to Customer Services. Seems like I am not getting anywhere. I'm due a refund which I've been waiting months for. The customer service is absolutely poor.