Utility Warehouse are a dishonest organisation that does not have the integrity that would be expected for them to be allowed to provide utility services in a developed country. They are only able to continue trading because the reorganisations of EnergyWatch, ConsumerDirect, etc mean that there is less effective control of the utilities businesses than there should be. You should not expect any help or sympathy from them.
Four options that are available to you are:
Arrange for a repair of the phone yourself.
Purchase a replacement phone and put your Utility Warehouse sim card into that.
Pay the early termination fee or continue the contract.
Dispute matters with Utility Warehouse. If you do this, you should be aware that Utility Warehouse will take all steps, legal and illegal, to recover money from you. This could include taking the matter to court without telling you the hearing date and/or lying under oath in court.
Being unhappy with the length and cost of the contract are not adequate reasons to dispute matters unless you were not properly informed of the details when you agreed to the contract, in my opinion.