Never trust. They don't and can't control any support channel. No automated procedure. All are on their hands.
I ordered on Saturday and then I found I used invalid card.
I left a cancellation request in 10 mins using their all support channels: call, mail, chat, and web query. I even chatted with their third party support agent. She told me that she will "forward" my query.
All were ignored.
On Monday their worktime, they gave me the number. I am sure they noticed my cancellation request and still ignoring.
Note: their company address is a virtual shared office. They do not have a physical office.