[CLOSED] Can't record via USB from DJM900NXS to laptop?!

My setup is: DJM900nexus, CDJ2000nexus, RMX1000 and S DJ08 speakers straight into the djm900nexus.

I am running my djm900 nexus into my laptop (Dell Latitude 6420) via the usb connection. I have the mixer output set to record out for channels 3 & 4 and the mixer input channel set to usb 1/2. 

I have audacity set to djm900nexus for both input and output device. I have the sample rate set to 48kbps for everything but yet nothing records!

I spoke to someone at Pioneer today who told me the usb is only for input such as a midi controller and I am best to use the line-in?!

I am sure this isn't the case so is there any chance you can finally solve this problem I am having please?

All the best

Neal