I agree with what SQ59 said. At the same time, you absolutely did the correct thing to bring the situation to the attention of someone at the RCC (and I can only hope that that person escalated it to RCC senior management rather than just shrugging and walking away). My hope is that UA would follow up with airport management; UA pays a TON of rent for the RCC and the kind of abuse you put up with (whether to your face or through the wall) is not good for UA's business.