How to escalate issues with a Fiorese seller?

Hi everyone! Looking for help. I have an issue with my Fiorese order -- basically due to a Whatsapp malfunction, the colour of the gem I chose was not labelled properly and now the gem on my order is wrong. I am asking the seller to rectify, but I feel that we are just going around in circles. It may be a language barrier as it seems they are not reading the screenshots I sent on my end to prove the miscommunication. I was wondering if there was a manager anyone has spoken to in order to help resolve issues?