Hi Khokha-lola,
Thanks for using Apple Support Communities. From our understanding, you are missing a cable that was expected with your Beats, do we have that right? Based on the photo, it looks like everything that comes with your Beats is present. According to this link: BEATS SOLO3 WIRELESS , the box contains, Beats Solo3 Wireless headphones, Carrying Case, Universal USB charging cable (USB-A to USB Micro-B), Quick Start Guide, and Warranty Card.
Hope that helps!