Forrester UK Holdings

If you are offered finance for products by these people, check your small print and buyer beware. These people will not enter into discussion with you if you have a problem, they just send bills....
We got our debt with them via a card terminal issued by Lloyds TSB.
We had a dispute with Cardnet. Their response was to cancel our service.
That left us with 2 terminals we couldn't use tied into a 4 year contract.
Forrester will not provide info as to any other banks we can use their equipment thus rendering it useless so we are refusing to pay.
Stalemate, they bill us, we ignore it but guess who will still be liable in the end....
Type in Forrester uk in Google - LOADS OF COMPLAINTS of similar Ilk.
Can we as a body tackle these companies? Any ideas?