Sprint is defending its service termination of 1000 customers that called customer service frequently, saying that only the most frequent abusers of its free customer service lines were targeted and the volume of calls they generated detracted from other subscribers’ own customer experience.

Late last month, Sprint sent out a letter to about 1000 customers notifying them that their service would be terminated at the end of their billing cycles, giving them until the end of July to port their numbers over to another operator. The reason Sprint cited: too many calls to customer service about their bills, service plans and often unrelated matters.

“While we have worked to resolve your issues and questions to the best of our ability, the number of inquiries you have made to us during this time has led us to determine that we are unable to meet your current wireless needs,” Sprint told the customers in the letter.

In an interview with the Associated Press, a Sprint spokeswoman said that the customers targeted by the audit were the smallest minority in its overall customer base and were typically subscribers that phoned customer service 40 to 50 times a month, often pursuing issues Sprint said it had already resolved or making inappropriate requests such as other customers’ records. With an average customer calling less than once a month, a small stable of subscribers calling more than once a day brought down overall quality and wait times for customer service overall, the spokeswoman told the AP.

This isn’t the first time Sprint has tried to reign in customer service calls. Several years ago, Sprint tried to offset its rising call center costs by charging customers $5 every time they called customer service. The charge produced outrage from its customers, and Sprint quickly dropped it.