INCORRECT REPAIRS

My car was displacing an ABS sign then i took it to Toyota for assessment. I was given a quotation after the assessment of the car. the quotation required that i must buy a sensor. I purchased the sensor and Toyota installed the it for me. I was informed but the mechanic that the sensor is for an airbag but my car does not have an airbag, regardless of me informing them that my car does not have an airbag they still installed the new sensor. I asked whether the sensor has a dual function and the said no, it is only for the airbag which I don't have. I brought the complaint forth to Toyota management but he was not interested in assisting me in my problem. They have refused to take back the part and refund me. I feel like i have been mislead. I would really appreciate if Toyota could refund me both for the assessment fee of the car and the sensor they quoted.