A possible (likely) scenario is that they dropped the subframe to do the clutch repair, and when they replaced the subframe, they did not get it properly aligned. This caused the wheel alignment problem you were talking about. If the subframe is out of alignment, it can put strain on all the wheel/axle/cv/etc components, which can make the cv's wear quickly.

95 Contour Zetec, ATX (wrecked, sitting in the barn) 95 Mystique Zetec, MTX 2000 Taurus SEL 3.0L Duratec 1994 Crown Victoria LX 4.6 V8 1993 Chevy Silverado 4.3 V6