I have successfully restored more than 300 lost pictures and video files from my Canon EOS 80D camera's memory card. Although not a 6D, I think the principles of data recovery are the same. I hope you haven't continued shooting new pictures or videos after formatting your Sandisk SD Card. Otherwise the deleted images are likely to be overwritten by new generated files. By the way, I was searching for "canon photo recovery" on the Google to find the right data recovery tool. Good luck!