Trade associations
Many industries have trade associations. These are bodies that are regulated by their members but impose certain agreed standards as a membership condition.
Many trade associations have a code of practice or conduct, and all have a complaints procedure, which can be used to resolve individual cases.
Trade associations exist primarily to protect their members. However, they can be useful in changing the behaviour of an individual company, as trade associations do not want the good name of their members to be affected by the poor behaviour of one company. The peer-group pressure they can exert, either through a complaints procedure or less formally, is probably much greater than the pressure an advice agency acting on its own could create.