If the council has not been able to successfully resolve a complaint to a customer's satisfaction, they can contact the Local Government and Social Care Ombudsman (LGSCO). This should be done within 12 months of when the customer first knew about the matter they are complaining about. The LGSCO will then communicate with the council regarding the issues.
The LGSCO can be contacted by calling 0300 061 0614 and more information can be found on their website.