A 69-year-old woman from Guelph, Ont., who says she was forgotten on an Air Canada flight in April spent roughly an hour trying to stay calm, so her asthma wouldn't flare up.

It was one of the several health issues Pamela Prescod worried about during the ordeal. She's legally blind and needed wheelchair assistance off the plane. She says a flight attendant was going to come back and help her fill out her customs papers but never did.

"I started yelling, 'Is anybody on this plane? Is anybody on this plane?' And nobody responded," said Prescod.

"My biggest fear [was] that I could go into diabetic shock and die."

Prescod is speaking out about her experience, after realizing she isn't the only passenger to be left behind. Air Canada said it would review an incident that was reported earlier this week, in which a woman from St. Thomas, Ont., woke up alone on a cold dark aircraft.

On April 6, Prescod was returning home from a trip to Barbados, where she'd been visiting family. The flight had landed in Toronto sometime between 8:30 p.m. and 8:40 p.m., she explained.

More than an hour had passed before a mechanic found her, and let her use his cellphone to contact one of her daughters.

"He was flabbergasted," said Prescod.

Debbie Louttet says her mother's call came from a long distance number she didn't recognize at 10:02 p.m.

The mechanic went to get help, and Prescod says she was taken off the plane, ushered through security and led to the arrival gates where she was reunited with one of her daughters, Jacqueline Swan.

Swan had heard from Louttet that their mother was still on the plane and had been trying, unsuccessfully, to get help from airport staff.

"They [told Swan], 'No, that can't happen. She probably went to the bathroom,'" said Prescod.

Louttet says the mechanic told her mom that each of the plane's flight attendants were supposed to fill out a checklist.

"He said he went and checked the sheet, and all three of them had checked off that they had checked the plane, and it was empty," she explained.

Although she's doing better now, Prescod says she was sick for three weeks afterwards due to the stress. She was lethargic, and her daughters had to help her eat and bathe.

"They took me to a doctor, and he said it was too much stress. It was traumatizing," Prescod said.

We were deeply apologetic about this upsetting incident, where our customer did not receive the wheelchair service she had requested… - Air Canada, in a statement

Prescod confirms that Air Canada contacted her the day after her ordeal and apologized. It also refunded her entire fare and gave her a $500 voucher.

"We were deeply apologetic about this upsetting incident, where our customer did not receive the wheelchair service she had requested and, due to a miscommunication among our crew, the customer waited for her wheelchair on her own," Air Canada said in a statement.

Air Canada admits 'serious service failure'

The company admitted to a "serious service failure," and said it had undertaken a review of on-board service protocols.

The senior adviser of communications for Toronto's Pearson International Airport, Robin Smith, tells CBC News that airlines — not the airport — are responsible for passengers.

"The airline is responsible for checking in their passengers, for greeting them at the boarding bridge, assisting them on and off the plane, and serving or handling all the needs of the passengers on the aircraft."

They dropped the ball, and then they dropped the ball again. - Pamela Prescod

Prescod, who "always" travels with Air Canada, says she won't be getting on another one of its flights until an eye operation restores her vision.

"They dropped the ball, and then they dropped the ball again," she said.

"I think they need to train the staff to double check," said Prescod. "If they found they were lying when they checked and said everyone was off the plane … they should be fired."