"I'm sorry that you feel that way," said the service representative when I called to complain about his, in fact, very bad service. Is this an apology? What about what he did wrong and what he plans to do to amend the situation, if not for me directly at least for future customers?

"I'm sorry that you feel that way" is just a way to shut the customer up without admitting to any culpability.

I'd rather hear, "you are wrong and here is why". Then at least I could say, "I'm sorry that you feel that way".