QVC has NEVER given 24 hours to cancel an order. Back in the day, they used to give you four hours. Now it is about an hour at best and then it goes to “processing” which means no cancellations. Of this I am very certain. HSN gives you until midnight on the day you ordered to cancel, which is really very generous. I am not familiar with any vendor that allows cancellations up to 24 hours. Here is HSN’s explanation from their FAQ’s:

Note: In order to ensure you receive your orders as quickly as possible, we begin the shipping process for the previous day’s orders at midnight Eastern time. Orders must be cancelled before 11:59pm ET on the same day they are placed. If you wish to return an item, please follow the instructions on the label included in your package.