MYpearson Customer Service Issues

I placed an order for a $[redacted] book and a MyMathLab access code. I mistakenly chose ground shipping instead of overnight for an additional $8. I emailed customer service three times to rectify this before my order was shipped, but then received an email stating the book is backordered for up to 30 days. Despite this, my credit card was already charged. I have requested to cancel the order via email but have not received a response. I need my order canceled and a refund as soon as possible as my class has already started, and I cannot wait for the backorder period and additional shipping time.