Traders in the Mandurah Forum and many businesses on Tindale Street and Park Road in Mandurah's light industrial areas lost thousands of dollars in revenue after they were left without power yesterday.
Dedicated employees at Hot Klobba on Park Road continued to work through the blackout, by candlelight and torchlight.
Owner Jane Tomlinson said they could not ignore customers who had placed orders, including families who needed to pick up uniforms for children who were starting school today.
She estimated they had lost about $2000 in sales revenue because their Eftpos machine was not working.
Park Road Lunch Bar owner Tracey Gregory said she had lost $2000 in revenue after the blackout forced her to close her doors. "I will lose another $3000 in stock if the power does not come on soon," she said.
"The power went off at about 2.30pm (on Sunday) so power to the freezers has been off for almost 24 hours."
Mrs Gregory said it was a major blow to the family business but she understood no one was to blame.
"At least we haven't lost our roof ," she said.