Bank calling me for my father's past due car payment when I am not even on the loan! What do I do to stop it?

My father fell behind in his car payment, so I called the bank Wachovia and made the payment for him to try to catch him up. He was already 2 payments behind but I could only pay one. Needless to say, he is about 30 days behind every month, last month someone tapped into his checking account by Pay-Pal along with my Uncle's account too. This is not the first time this has happened, we are trying to get to the bottom of that problem but it has made his payments bounce. Now since I made the payment I have his auto bank loan calling me to make the payment, they have basically told me "Well if I cared enough I would pay it again", have screamed at me on the phone after I have screamed at them that this is not my responsibility, "well then it shows you don't care about your father", "do the right thing and pay for it", I have called and pleaded to stop calling me, they are calling me on my cell phone and I have a very limited plan and it is wasting my minutes too, I've told them this too. I have received according to my cell phone records, over 30 calls and nasty messages, the "one" supervisor really screamed at me about I was now being irresponsible for not being there for my father and I should do the right thing. Then they claim they can't bring up the information because I don't have the account number to remove my number. He has 8 months left on this car and due to my mother ping and losing her income and he did work but as you know the economy being the way it is, he has fallen so short with monies. He is trying to keep a roof over his head, has let all his credit cards fall, but his emotional status is not good, so he is coming to live with me in April and I am trying to get him straightened out. What can I do about these calls? Do I have a right in any of this? Why are they making me out to be the bad person? It hurts that they are doing this and they are making me become a person I don't want to by screaming and hollering at them back with profanity, I'm just so frustrated that they are acting this way. Your input would be great!