Sounds like cobblers to me, the turntable is stereo so there's no reason why it should be mono, unless you've got an option within Audacity set to record in mono. I don't know why the Acer people are saying anything to be honest, it's not their software and it's not their turntable, the PC is virtually irrelevant in this instance.
I'm using a Pro-ject Debut II turntable into Pro-ject's USB Phono stage and recording with DBPowerAmp's auxiliary input convertor. It doesn't do any kind of clean-up operation, so you'll need to make sure the vinyl is clean but it works pretty well and encodes into FLAC.
It has an auto-detect function for starting and finishing tracks but this obviously doesn't work with continuous recordings like Queen's A Night at the Opera and it can have trouble with badly recorded albums, such as Eli "Paperboy" Reed's debut, which is such a poor quality recording the noise level never drops low enough for it to detect the gaps, which is bluddy irritating. There's no technical problem, I recorded another album straight after giving up on that one and it was fine, so it's just the recording.