1. Member States shall ensure that adequate and effective means exist to ensure compliance with this Directive in the interests of consumers.
2. The means referred to in paragraph 1 shall include provisions whereby one or more of the following bodies, as determined by national law, may take action under national law before the courts or before the competent administrative bodies to ensure that the national provisions for the implementation of this Directive are applied:
(a) public bodies or their representatives;
(b) consumer organizations having a legitimate interest in protecting consumers;
(c) professional organizations having a legitimate interest in acting.
(a) Member States may stipulate that the burden of proof concerning the existence of prior information, written confirmation, compliance with time-limits or consumer consent can be placed on the supplier.
(b) Member States shall take the measures needed to ensure that suppliers and operators of means of communication, w