Refund for non installation

From the 4th of March 2021 I've been texting using the whatsapp line and no connection to an agent till today. I get a massage saying a callback request has been sent but no one calls me back. I need a refund for an installation that didn't happen on the 26th of February. I've tried even speaking to them via facebook messager but no response. I've honestly have not experienced such bad customer service in my entire life.