Apple is under fire once again in the United States, as the local government wants answers regarding the company’s iPhone slowdowns taking place on older models with depleted battery cells.

Sen. John Thune, chairman of the Senate Commerce Committee, has sent Apple’s CEO Tim Cook a letter to ask for more information on how the slowdowns took place, as the practice has been heavily criticized by customers and consumer groups and described as planned obsolescence.

A report from the WSJ reveals that Senator Thune “asked how Apple has tracked customer complaints of processing performance and if Apple has explored offering rebates to customers who paid full price for a battery replacement before the company offered discounted rates last month.”

A public response or an official statement from Apple hasn’t been offered just yet, but the discussions are likely to remain private at this point.

Legal trouble across the world

Shortly after Apple publicly admitted that it slows down iPhone 6, 6s, SE and 7 models on purpose in order to prevent unexpected shutdowns on units with degraded batteries, the company was hit with a plethora of class-action lawsuits in the United States, with some asking for as much as $999 billion in damages.

The company has also been required to provide more information on the way the slowdowns were implemented by South Korean authorities, and more recently, France started an investigation to determine whether this practice can be considered planned obsolescence or not. According to French regulations, planned obsolescence is illegal and could lead to a hefty fine for the company.

In the meantime, Apple has launched a battery replacement program offering repair services to impacted models at a discounted price of $29, down from the original $79. The firm, however, has a hard time dealing with the growing number of requests for battery replacements, and the majority of stores are either full on appointments or no longer have any battery units in stock.