Psu died ?

Went in for a case swap and was told that everything moved over fine except that my psu died? I was just using it last night and today after case swap it no longer works. They said they used their own 500w psu to test and it works. I have a Cx750m psu. It powers a i5-12600k , 32gb ddr4 corsair vengeance and an rtx 3060. Shop is encouraging me to rma psu but seems weird that all of a sudden it just died ?