Green Star Energy

I switched from my old supplier (GB energy now referred to as Coop Energy) to Green Star energy back in January. I mistakenly gave Green star an incorrect reading at the date of switch. This means that my old energy provider sent me an incorrect bill of £400. I am actually owed over £100 by my old energy company. Almost straight away (beginning of feb), I rung Green Star and informed them that the gas reading was incorrect. They said they could work out what the approximate correct reading was if I rung back with 2 more readings. I took two readings in February and passed these back to the company at the end of February. Ever since the end of February, I have been calling Green Star every couple of weeks or so to chase this up, as GB energy have not received anything from them to confirm the agreed read. Every time I have called, I have been told there is some backlog, or there was a delay in processing the agreed read, but that this is sorted now and the agreed read will be done within a week or so. I have on several occasions expressed my wish to make a formal complaint, and every time have been told that the agreed read will be processed imminently and that there isn't anything to worry about. It has been very difficult to get Green Star energy to acknowledge my complaint, I have several times expressed that I wish to make a formal complaint, and every time I have received no acknowledgement that my complaint has been logged, only a loose promise that the agreed read will be done very soon. Finally over one month ago, I asked to speak to a manager and ended up speaking with a representative from complaints, who promised to get my agreed read done urgently and call me back that same day to confirm that this has been done. One month later (and I have called up within this time twice to ask to speak to the complaints representative) but was told she would be in touch with me), and I have heard nothing back from Green Star. I have now wasted hours and hours of my life on hold to this company, waiting for calls back, being disconnected -it really is not worth the hassle for the cheap prices!