Abysmal customer service. Nationstar took over my ...

Abysmal customer service. Nationstar took over my mortgage not too long ago, and I have discovered that they are not crediting my payments to my account, and have now reported me as delinquent. I have proof of my payments being processed, but I can't get past their collections robo call center. They refuse to give you an option to speak to a human being. Infuriating!!! They can't process payments, and they won't talk to you. How are they still in business???