OTTAWA -- Persistence paid off for one Ottawa resident who refused to accept the cancellation of her COVID-19 vaccination appointment on less than 24 hours' notice.

It’s the day Betty Thurston has been waiting for. On Wednesday she got her shot and says it was fast, easy and efficient.

"I showed up ten minutes before my appointment time and I just had a chance to park," says Thurston. "My number was called and I was vaccinated before my appointment date ... it was a very, very slick process."

Only, it nearly did not happen.

Thurston booked her appointment three weeks ago. On Tuesday, less than 24 hours before Thurston’s appointment, she received a call from a provincial health agent who said her appointment was cancelled.

"I said, is this a prank? I thought it might be a friend but she said no, no it’s cancelled and I said I’m sorry but that’s unacceptable," says Thurston. "I wanted to know the reason but there was no reason given. Had it been we’re overbooked or we don’t have the serum, I would have understood."

To add to the complication, Thurston was also told she would not be able to reschedule. 

The Ontario government points the finger at a two-week-old problem, where about 3,100 Ottawa residents were double-booked to receive the jab at the Nepean Sportsplex. The error was announced March 19 and at the time the city of Ottawa said the affected appointments were for March 23 to 25.

In a statement to CTV News Ottawa, the Ministry of Health called the cancellations an isolated event. 

"Due to the recent provincial announcements that vaccine bookings were available, residents aged 70 and older city-wide, all available appointments have been booked up until April 7," said Emergency and Protective Services General Manager Anthony Di Monte in a statement to CTV News Ottawa. "As the city receives more vaccines from the province and the provincial booking system is updated, more appointments will become available."

"I wasn’t going to accept it," said Thurston.

Betty was going to keep that spot, and insisted there was no other option.

"I mean you’re all geared up for it; you're anxious, so you want to go through with it," says Thurston. “When I spoke with the lady, I said you have to have known why would you call me this late in the game but she didn’t have an answer. She just kept saying, 'I’m sorry I just have to cancel your appointment.'"

Thurston says after about 10 minutes on the phone, the agent conceded.

"Given my experience, I would tell them to be persistent and keep on fighting and don’t give up," says Thurston. When asked if this was a matter of 'the squeaky wheel gets the grease,' she laughed, and agreed, adding, it’s unfortunate and should not be that way.