This Scheme uses Adjudication.
Adjudication is a process by which an adjudicator, who is legally qualified, weighs up the documents and evidence provided by the customer and the trader in order to reach a written decision. The adjudicator will take into account the law relevant to the subject matter of the dispute at hand as appropriate.
Referenceline was founded in 1997. They collect and publish independent customer feedback (reviews) about businesses, measuring their performance against agreed Codes of Practice. referenceline work with professional bodies, Trade Associations, Local Authority "Trusted Trader" schemes and others to monitor and promote the performance of their member businesses.
Raise your concerns directly with the developer.
If your complaint is not resolved to your satisfaction by the developer you may submit an application to CEDR for adjudication.