The Citizens Advice Bureau have lots of information about: benefits, civil rights, consumer rights, employment, housing, immigration, etc... See also their on-line version
Shelter Cymru (advice on accommodation problems) have surgeries in Aberystwtyh
Ask The Police - general public's most frequently asked policing questions
The Public Services Ombudsman for Wales is the official body to complain to if you suffered through maladministration or service failure by a public body including local & national government, National Health Service, and many more