Green Star Energy

I've had great difficulty with this Supplier while trying to recover a Credit Balance in excess of £500.
I've been trying to reclaim this money since the beginning of July and despite several promises that this money would be refunded to my Bank Account "within 14 days" no refund has been forthcoming.
Today was the last straw - I was on the phone with Green Star for 30 mins without receiving any satisfaction. I asked to speak to a manager about my issue and was informed someone would call me back "within the hour". I asked for and was provided with an e-mail confirming this. I waited by my phone for 2.5 hours without any call back. I then called Green Star again at 16:30 today. My call was answered in the usual way and i was asked to hold on for a minute. After 30 minutes of hold music I was disconnected!!!
I intend to contact Ofgem/Energy Ombudsman tomorrow. I will update this thread as things progress (hopefully).
Please remember my experience if you are considering using/switching to Green Star.