Disregard of customer rights and dignity

I received the most shocking customer service from the collections agent (Sarah) this morning. The collections agent asked me to verify my date of birth which I did. She proceeded to ask me to verify my email address, which I asked her to verify instead since she has my details on her system. Sarah told me not to give her attitude and that I must know that she is going to continue calling me whether I like it or not and ended hanging the phone up. Due to the fact that I'm also in the service industry I called Sarah again and asked her if she is aware that all customers , even if they are in debt need to be treated with respect and dignity. She immediately became defensive and asked me if I was polite. She was raising her voice, which I made a point to highlight to her but she continued and told me I'm shouting when I wasn't. When I asked to speak to management she put me on hold for sometime and said Sumaya Peterson who is the supervisor is busy and I must call back. It is highly disappointing that a law firm can have this caliber of staff that disrespect and in an undignified manner.