destratar

Not in the RAE dictionary itself, but widely used in Argentina and Uruguay (and recognized in the Diccionario de americanismos) to mean treating someone rudely, dismissively, or disrespectfully — roughly 'to mistreat verbally.' The related noun destrato (rude, inconsiderate treatment) is common in that region, especially in discussions of customer service or healthcare.

• El empleado destrató al cliente sin ningún motivo. — The employee was rude and dismissive to the customer for no reason.
• Se quejó de que la habían destratado en la clínica. — She complained about being treated rudely at the clinic.
• No hay que destratar a nadie, aunque el día haya sido difícil. — You shouldn't be rude to people, even if the day's been hard.

Using destratar outside the Río de la Plata region and expecting it to be universally understood — in most of the Spanish-speaking world, maltratar (verbally) or tratar mal is the neutral choice.