Unable to purchase on Samsung online store.

I am very unhappy with service I received today with Samsung customer care service. I was trying to purchase a mobile from Samsung online store but was receiving an error message saying " we're sorry but your transaction couldn't be completed at this time, please try again or contact customer service. I called customer care twice and they advised they will call me back no one did and give feedback as they have escalated it. The third time I called the consultant advised she will call me back, she later calls me back after 5:30pm that they have escalated it but got no response and I should try purchasing from another device but I get the same error as I have try purchasing from there different devices and also used two different cards. They are unable to provide me with a valid reason.