OTTAWA -- After getting his first dose of the Moderna vaccine on April 19, Steve McArdle was instructed by doctors to have his second shot no later than May 17.

"I'm immunosuppressed. I've had a liver transplant," said McArdle, 62.

When he got his shot at the Eva James community clinic, he said he was given a piece of paper with instructions to book his second shot online, but because the province extended time between doses, the system only allowed him to book for August 9 or later, well past the May 17 deadline.

So, he called the health lines.

"Ontario health is telling me to call Ottawa health. Telehealth they told me to call Ontario health or Ottawa health," said McArdle. "It's just a back and forth."

He's called every day, getting the same answer.

"It's 'Sorry sir, I don't know how to change the date'," he explained. "Day after day goes by and day after day gets closer to when I need my second dose.

In a statement, Ottawa Public Health says organ transplant recipients need to pre-register on their website. Individuals who meet the criteria will get a call to book their appointments and will be scheduled at the recommended dose interval.

McArdle said he did go to the website, the response he got was that someone would call him in a couple of weeks.

For now, he says he'll keep trying by phone, hoping time won't run out.

"As soon as the office opens I'm back on the phone," he said. "I'm raring to go whenever they're ready to give it."

In a statement to CTV News, the Ministry of Health said people in the highest risk category are to call the clinic where they received their first dose to schedule their second.

"Individuals in the highest risk category who have received a letter from their hospital / clinic indicating they are eligible for a shortened second vaccine interval can call the vaccine clinic (where they received their first dose) to receive their second dose," the statement said.