Poor service

Today I was queueing at the money market. As soon the person in front of me moved I walked towards the counter. In fact I stood in front of the lady behind the counter because I was next to be serviced. I stood there for about 10mins without a word from her while she was busy with I dont know what. Moments later I asked her if she was available or not. She said I'm still serving this gentleman (pointing at an old white man on my far right) which I had no idea she was assisting. I asked her why aren't you excusing yourself and tell me as a customer that you won't be long you still busy? She said I thought you can see that I'm busy. I said to her I'm a customer I can not just assume, I expect you to update me on what's the hold up behind the counter because I'm expecting a service. She kept quiet. Even the supervisor didnt intervene, she just stood behind her colleague and said nothing. so unprofessional of her. This was about 15:30. The lady had cornrows ( 2 thick ones & 2 thin ones in the middle) the supervisor had a red/orange short braids. It was so pathetic. Do they send these people to customer service training or not? Really their service is like they are doing customers a favor.