Not sure what you mean you think you overpaid. Centrelink calculates payments against income, which you say you declared accurately. Tax return have nil to do with Centrelink payments - in fact any offsets are auto calculated against Centrelink income. Or any income. So I’m at a loss as to understand that you feel entitled to be back paid? Also, as a chronic mh condition sufferer, I have never expected let alone been offered concessions to citizen obligations due to my condition. And in any case, with c-ptsd also on my health record, I can affirm that it is not currently considered a real condition (Medicare and Centrelink currently go by dsm so you’d need to massage it to fit a valid designation).