There is a sequence that you should follow to fix front end clunks. First is to get under there and tighten every mounting bolt that has to do with the front suspension & steering. This includes the front sway bar mounts, the end link grommet and lower end link bushing, the control arm bushing bolts and mounting bracket, the big nut at the top of the strut tower in the engine compartment (a special tool is needed for this, or an impact wrench), and the front crossmember mounting bolts (accessible from the engine compartment, down low on either side).

In my experience, half of the time it's just a loose bolt somewhere.

The next thing to check would be worn bushings. Most likely it would be the control arm bushings. If they're bad you usually can't see them, and you often can't feel any looseness by hand, so they could be missed even by a reputable shop. If the car sat for long periods of time it's quite possible the rubber in the bushings got stiff and broke when you started driving it. These bushings are not very expensive (make sure you get the OEM or genuine Volvo bushings, not Scantech), and the control arms aren't very difficult to remove from the car and take to a shop to have them press the old bushings out and the new ones in. You'll want to do both control arms, not just the offending side. There are other bushings that can be bad, such as the end link bushing and grommet, and also the sway bar mounts, but my prediction is that if tightening up the bolts doesn't fix it, it will be at the control arm.

If changing the ball joint fixed it, and it came back, it's possible (though not likely) that the new ball joint was damaged when it was pressed in, or perhaps they used an inferior replacement part.

With such low miles, I doubt very seriously that it's either your strut or your strut bearing, but they can cause clunks while turning and going over bumps in vehicles with a lot of miles on them. The strut bearings are very tough, so I really don't think that's it. I'd lay money on it being a loose mounting bolt or the control arm bushings.

Under what conditions do you hear the clicking?

If it happens at wheel speed, it could be a wheel bearing (usually a low-speed growl, though), or even something hitting a brake rotor. If you hear it going over bumps or road irregularities, it could be the strut bearing.

Give us a little more info to help you diagnose the problem. Otherwise, someone here (even me) would be willing to take the car off your hands cheap!