All universities have a formal complaints procedure. If this does not lead to a satisfactory outcome, you can take up your complaint with the relevant national complaints organisation. But start by talking to the students’ union.
In England and Wales, the relevant national organisation is the OIA – the Office of the Independent Adjudicator for Higher Education (www.oiahe.org.uk). This provides an independent system for students to make complaints about universities – but only if they relate to a study or research programme, a service provided by the university, or a decision on eg a disciplinary matter. It cannot deal with matters of academic judgement, court actions or employment etc.
In Scotland, a similar system is operated by the SPSO – the Scottish Public Services Ombudsman (www.spso.org.uk). It deals with complaints against any organisation providing public services in Scotland, including higher education.