This solution may be not the ideal but is a very good start and is used by very big players. You can receive the orders on your call center and then contactthe business by phone to transfer the orders.
As you know there are lot’s of businesses that don’t have computer, internet or cellphone for the business. Well instead of making them invest on your service before even trying you can offer this very good alternative. Of course when they see that your service works for them they will want to invest on another solution to receive the orders directly.