When should a customer be advised to contact their wireless carrier?

Advising a customer to contact their wireless carrier for SIM lock issues is important because such issues are typically related to the carrier's policies and services. A SIM lock restricts a mobile device to work only with a specific carrier's network. If a customer is experiencing problems with their SIM card, such as being unable to use their device with a different carrier or needing to unlock their device for international travel, the correct path for resolution is through the carrier. They have the necessary tools and authority to address these concerns, including unlocking the device if appropriate.

On the other hand, battery issues, device performance issues, and software installation issues are generally matters that can be resolved through troubleshooting steps that involve the device itself or the operating system, rather than direct intervention from the carrier. Customers experiencing those problems are often encouraged to seek assistance from technical support or to visit an Apple Store or authorized service provider instead.