When we say "use your words" during an emotional moment, we are trying to help our children come to a place of regulation. Unfortunately we are using a tool that they cannot access at that moment.
The reason they are not using their words, is because the language centers of the brain are being flooded with reactionary neurochemistry. Which means that hearing instructions via language isn't going to work either.
Instead, communicate with your non-verbal presence so that your child can FEEL your support to help their brain regain a sense of calm and connectedness.
After the emotional flooding has subsided and their thinking brain is above water again, they will be much more capable of using their words and helping you understand what was happening for them.