Using Mos Net Order

• What are the system requirements for using Mos Net Order?
• Can I use Mos Net Order with a feature phone?
• I received the following error: "Your chosen store is currently too busy to accept your order either because of the time you set to receive it or the method you chose to receive it."
• I do not understand how to use Mos Net Order.
• I want to check out, but cannot go on to the checkout page because of the following error: "You cannot check out with your current order. Please review your order."
• What should I do if I replaced the mobile device currently registered with my Mos Net Order Member account with a new one?