On Friday, the company announced a new program to replace the USB-C cables that came with 12-inch MacBooks sold through June 2015. According to the company, these cables can stop working due to a design flaw. As a result, your MacBook may not charge reliably when using a defective cable with a power adapter.
Otherwise, you’ll need to contact Apple, visit your local Apple Store, or get in touch with a local Apple Authorized Service Provider to get your new cable. Head on over to the Apple Support site to get the full details of the replacement program, and to find out if your MacBook qualifies.