Firstly; stop applying for more credit, further declined applications will only serve to further degrade your existing credit rating.
Secondly; Never go to the private fee charging companies, instead seek the immediate free help of any of the professional charitable organisations below. After preparing a income and expenditure balance sheet they will be in a position to identify your essential living costs and suggest where savings could be made, restructure your existing payments, or ensure that you are receiving everything that you are entitled to.
The debt of £7k is not huge by some standards and can soon be sorted out, but if you are struggling to make payments then you need some external professional help to balance the accounts.
http://www.citizensadvice.org.uk/
http://www.cccs.co.uk/
http://www.nationaldebtline.co.uk/