Exchange immediately. Ask for an unopened unit. The mod wheel problem is not one I've heard of.
The clicking is a little more vague. It's possible you're hearing what happens when you have freerunning oscillators and quick analog envelopes - a kind of tick. Most audible with low cutoff settings.
But if it's more of a high volume sound that does not seem like it's being generated by the envelopes or a non-zero-crossing attack, then you have a second problem. But the mod wheel sounds busted - explain and return.
GC and other places get returns back daily. I'm not sure they have the best process. A sales guy takes the unit, might make some notes about the problem. Someone else probably inspects it, thinks there's no problem, and repacks it for another sale.