Scandal - heartless lack of availability (6)
I believe the answer is:
outage
'lack of availability' is the definition.
'outage' can be an answer for 'lack' (thesaurus). I'm not sure about the 'of availability' bit.
'scandal heartless' is the wordplay.
'scandal' becomes 'outrage' (scandal can mean an occasion for public outrage).
'heartless' suggests removing the centre.
'outrage' with its centre taken out is 'OUTAGE'.
Can you help me to learn more?
(Other definitions for outage that I've seen before include "Gap in power supply" , "When one lacks power" , "time of no power" , "loss of power" , "Power cut" .)