Order handling software. What are you using ?

hello,

I was wondering what software anyone is using for order handling ???

We are looking for a software that could down load orders from Volusion, Amazon which in tern could set the way the order is shipped (when the order is set for free shipping we need to choose for the customer), from there our warehouse handler would login and transfer the orders to their system via API.

At the same time we need the orders to be downloaded into Quickbook as sales receipt.

We signed up with Teapplix but at the end they could not handle the API with Volusion's child products.

Please help.
Thanks!

I didn't find the right solution from the Internet.

References:
http://www.convergent7.com/forum/volusion-forum/managing-your-store...

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