STOP THE PRESSES! YOUR "XL" BIKE IS INDEED TO LARGE....

This could provide insight to the problem. Follow this link to your bike's geometry:

(Click here for Mach 2.0 Geometry)

Observe: there is NO size listed that covers 57-61 cm, as your salesman claimed. Rather, the Large size purports to cover 55-57cm, whereas the XL covers 58-60cm!!! As you identified in your post, your "58 cm" is the XL model, which is sized for riders 6'1" to 6'4"

Whether your salesman was dishonest or simply confused is of no moment. What matters is that if you got the X-Large, that would explain the horrible fit. It's not your imagination.