They are deaf, dumb, and blind, so they return not (to the right path).
صُمٌّ
(deaf),
and thus cannot hear the guidance.
بُكْمٌ
(dumb),
and cannot utter the words that might benefit them.
عُمْيٌ
(and blind),
in total darkness and deviation.
Similarly, Allah said,
فَإِنَّهَا لاَ تَعْمَى الاٌّبْصَـرُ وَلَـكِن تَعْمَى الْقُلُوبُ الَّتِى فِى الصُّدُورِ
Verily, it is not the eyes that grow blind, but it is the hearts which are in the breasts that grow blind. (22:46),
and this why they cannot get back to the state of guidance that they were in, since they sold it for misguidance.