The antonyms for the word "over-charges" are "undercharges" or "fair charges." These words denote that the pricing of goods or services is reasonable and within reasonable limits. Undercharging refers to the situation when the service provider or seller charges less than what is expected or worth of services or goods. On the other hand, fair charges signify balance, impartial, unbiased, and justifiable pricing, which neither over-charges nor undercharges the customers. Using appropriate antonyms like "undercharges" or "fair charges" during communication will help maintain a positive business relationship and ensure customer satisfaction. Therefore, it's essential to be careful while setting the pricing strategy for goods or services, as it can have a significant impact on the business's long-term success.