How Do I File An Associate Complaint Online?

I heard the Store Manager talking with the Assistant Store Manager while in her Office. She stated, "When she comes in again, I'm going to give her her money, and let her go". I wondered who she was talking about till night's end when she told me in front of the Asst. Mgr., "Have a nice weekend". I replied, "Why are you saying that, you know I work on Friday ... I'll see you then". She smiled while looking at the Asst. Mgr. and said, "Have a nice weekend". I knew then that the person she spoke earlier about was me.The situation is as follows:On register, Feb 07, with several people in line a Customer didn't have enough money on his card to pay for his purchase. Stating he's returning, I acknowledged, and with his wife and son sitting off to the side of the Store he left. I put purchase behind the counter, and asked the Mgr. how to remove the purchase. She was loudly talking about the man and his not returning that night or any other when a customer pointed out his wife and child was there waiting. She didn't care and kept ragging on the guy. I informed her that she was loud and the guy was not needing her demeaning comments, especially in front of customers. She got even more loud and obnoxious about it. I later made a comment to the Asst. Mgr. about her loudness and customer grumbling. He said nothing. The man did return half hour later and completed his purchase. I was embarrassed because of the Manager's mouthy complaints about the Customer and in front of all the other Customers. I'm being let go because I'm asking her to be conscientious about customers?? That's ludicrous!