National Tax Advisory review: Tax relief from back taxes owed to IRS

I received a voice mail from a company telling me that they could help reduce the amount of taxes owed to IRS. He said his name was Chris and he wanted to helo me. He asked me to sign an agreement before I knew the terms and fees for his services. He asked me a lot of questions about my income and finances that he needed to determine if I was able to qualify for the program. he left away from the phone to speak with his supervisor to get a determination on my approval. He said that they would get copies to verefy my credit and they needed me to e-sign their agreement that he said would would be $130 for 36 months. This came up to $4,680 if I couldn't pay their fee of $3500 up front. I also asked for their Employee Identification Number. He became offended that I would even ask for one. He must have thought that I wouldn't dare challenge his legitimate claims to have my best interest in mind. He thought because he had been so pleasant, I hadn't seen through his attempts to scam me. He accused me of trying to get out of an agreement that I hadn't agreed to. I tried to end the conversation, but he text me a long tirade about his sincere objected was to help me reduce my taxdebt. I didn't respond.