Constant harasing

The staff from the SSDA call centre continuously harasses me by phoning, they then want to to verify my details even though they are the ones contacting me. I will not verify my details over the phone to any one who I don't know. Credit ***** and ID theft is common. I do not have any Debt from any company that you are phoning me for. Please remove my details from your systems, otherwise I will not hesitate to lay charges against your company. To harass a person is a ******** offence. Your staff does not listen when one talks and the moment you try and talk to them they drop telephone calls.