Overstock.com review: Online purchase

Overstock has failed to reimbursed $570.28 after I've cancelled the order withing a 12 hours frame of an online purchase of a mattress. The order was made on June 19, 2020, and since that day I have been calling daily requesting the cancellation and until today June 30, 2020. Everyday when I call their 1-800 number I need to repeat myself all over again as no one seems to understand my case. It's has been a total frustration. All I've received are excuses from different service representatives. I've heard it all: "we are working home base, we have new employees without proper training, the warehouse team doesn't answer the phone, I will escalate this to the person that can assist"