NACCC are a membership organisation, and the centres we accredit are run independently of NACCC and therefore have their own complaints process. In the first instance, you should ask the centre for a copy of their procedure; this will advise you on how to make a formal complaint to the centre.
Once you have followed the centre’s complaints process and if you remain unhappy you can complain to NACCC. It is important to be realistic about your expectations though and really clearly explain what outcome you would like to achieve. Bear in mind that our role at NACCC is to ensure the centre followed its procedure and not to re-investigate or look at evidence.