I've just run a few checks on that company and its website.
Rebates UK Claims and Services Ltd has only existed since 6th October 2011 (although the website's domain name was actually registered 3 days earlier). It's run by 43-year-old Mrs Pilita McCrudden from her home address (on a recently built estate) in Stretford.
The company is in breach of the Companies (Trading Disclosures) Regulations 2008 by not showing its registered address on its website. (Perhaps Mrs McCrudden doesn't want disgruntled clients calling at 43 Marland Way?)
Many years ago I worked (on a 'commission only' basis) for a firm which claimed that it could get business rates reduced. Somewhat like Mrs McCruddden's website, the literature failed to mention that there were only limited circumstances under which valid appeals could be made. The company I worked for also required up-front fees but then 'conveniently' (for the directors) went bust after taking lots of people's money. The laws of libel prohibit me from suggesting that Mrs McCrudden might be operating a similar style of business but I certainly wouldn't engage her services (for something I could do for free anyway).
If you're really interested in the possibility of challenging your Council Tax banding you need this document (which explains the very limited circumstances under which such a challenge might be valid)
http://www.voa.gov.uk...sagree_ct_banding.pdf
Chris