********** cellular contract

This company called me and offered me a cellular contract. I agreed and they delivered. I realised later that they gave me a used phone which was refurbished and was used by someone before.The phone has problems and I can't just use an old phone. I informed them but it seems they want me to pay cancellation fees.How can I pay that when i didn't ask them to de***** me and give me a used problematic phone? People must be wary of them.