Help with My Cactus Please!

Please could somebody point me in the right direction.

My beautiful Cleistocactus strausii seems to be suffering, what am I doing wrong?

Thank you

Mark

 

The soil looks a bit too wet, and it also probably needs repotting.

 

I'd suggest that the bottom part may be dead , the shoot on the right looks ok but the roots may have rotted off completely.
Might be worth cutting a couple of stems off and drying them off for rerooting.