Rude call centre agents acting like I owe THEM money

I am being harrased during working hours by call centre agents who are BEYOND rude. They ask if this is me, yes, "please confirm your date of birth" why? You call me, it IS me. Then when I tell them I'm in the company of people and I will not now announce my date of birth, can we get to the reason for the call, they all YELL at me - like a child! I will not accept this kind of treatment when I am the one who voulntarily gave my number for a payment arrangement. Michelle today told me its "my job to tell her if this is not a good time to talk, it is not her job to ask me that" ***! Really!