You have several elected representatives at different levels of government.
Your 14 St Mary's councillors represent you on Isles of Scilly. The Council of the Isles is responsible for education, housing, planning, water and sewage and various other local matters including tourism, development and running the airport. Most councillors are not paid a salary, but get a basic allowance for the work they do.
Your St Ives MP represents you in the House of Commons. The House of Commons is responsible for making laws in the UK and for overall scrutiny of all aspects of government.
Lords are not elected by you, but they still get to vote in Parliament just like your MP. You may want to write to a Lord (more info).