This is basically the same question as here:
How to set ctrl+c to copy, ctrl+v to paste and ctrl+shift+c to kill process in xfce4-terminal?, but not a duplicate, because neither of the answers helped. Respectively, the first (the one not accepted), suggest to modify the

~/.config/xfce4/terminal/accels.scm

but I did that: I have changed 2 lines:

; (gtk_accel_path "<Actions>/terminal-window/paste" "<Primary><Shift>v")
-->
; (gtk_accel_path "<Actions>/terminal-window/paste" "<Primary>v")

and

; (gtk_accel_path "<Actions>/terminal-window/copy" "<Primary><Shift>c")
-->
; (gtk_accel_path "<Actions>/terminal-window/copy" "<Primary>c")

but neither of those helped, the interrupt is still assigned to Ctrl-c (I would probably need to make it unbind and rebind to Ctrl-C), but do not know how to do so.

1. How to map copy from ctrl-shift-c to ctrl-c
2. Remap interrupt from ctrl-c to ctrl-shift-c
3. Remap paste from ctrl-shift-v to ctrl-v