Dear sanny - The action I took worked because I did it all in one day and on four fronts and at least one must have hit home.
You must decide if this makes sense for you. In your position I would use chat to the box to get in touch with Chatterbox and say you are aware of the CHATTERBOX: NO CASHBACK posting on moneysupermarket communities and forum which has been routed through 'ask the expert' and in particular the CHATTERBOX - AN ALLEGATION thread which has around 200 views to date. You, sanny, are also aware that certain national media may be following this story and in particular one which has written adverse criticism about a cashback company, which has a presence online and in west London.
Then say
I am very worried that I may not see my money and would appreciate you paying my claim immediately. If you are not prepared or cannot do this I will reluctantly have to consider taking any action within the law to secure a payment from you.
Thank you for your attention
Kind regards
A very worried customer.
Once you have read this sanny you will be telling the truth - my detail is not there but that's all you need. I think they would be unwise to ignore you as I can push again for you in a slighly different way. I'll check in regularly.