Suspended OAS payments what year should it be reported in.

Have new client (widow), has not filed tax returns from 2020 on. OAS payment stopped in Feb 2022 as Service Canada said they could not contact the taxpayer (she moved and address was not changed). The client is over 90 and apparently never noticed the payment stopped. My question is do I report in the year it should have been received or when it is actually paid to her. I am thinking it should be when it should have been received. Yet CPP payments were not affected. ???