You could also get cash from that credit or debit card and hit up a bitcoin ATM, as long as you don't mind paying the markup. They're very convenient if you have one near you.
Exactly. If your debit/credit card was going to be accepted and is legit, then you can likely get much better rates just by withdrawing your funds in cash.
I don't know why but Simplex always declined my order and Banxa is very slow and they are asually cancel our order too
There is a reason why sellers are willing to sell coins through Simplex for debit/credit cards.
Their criteria is really strict, and if they have the slightest suspicion that they may be dealing with a fraudulent/stolen card, they stop right away. It makes sense - otherwise, how could they possibly compensate for the risk they're taking on?
Simplex and Banxa may look good on paper, but in reality, they probably aren't services you can depend on long term.