TheĀ next time these folks call do not answer the phone if you have call reject or call block use it if you have it on your phone. I would not stand for some one calling me a liar I would of told them to stuff it and hung up on them.
With call block and call reject all you need to do is dial acouple of #s infront of the phone but the phone company can give you more imformation on this,.
I would not give my bank imformation to any collection agency over the phone.
I would call Sallie Mae again and tell them you have this agency harassing you . I would also tell them you need another payment book and please send it out ASAP .