Shoppers Drug Mart review: Covid-19 vaccine refused to senior citizen

I took my mother to her Covid-19 vaccine appointment today at Yonge and Finch branch of Shoppers Drug Mart. She is 85 years old and finds it difficult to make frequent trips to the pharmacy. She was refused a Covid-19 booster vaccine shot on the grounds that 166 days had passed since her last booster and they need 168 days to pass. Shoppers Drug Mart requires a person making an appointment online to enter the last vaccine date, and so I would have expected the online system to disallow her from making an appointment if it was such a strict rule. Second, the pharmacy called us to confirm the appointment in the morning further giving us the message that it is no problem. Finally, I have received vaccine doses a few days ahead of time previously at other locations and apart from the pharmacist informing us that we are few days short, there is no issue and the administer the dose. There were what looked like a couple of young interns screening customers for Covid-19 appointments and they had no commonsense or human consideration whatsoever (they did not even look at my mother to notice how frail she was). I really found this treatment of a senior citizen unsettling and I want to complain formally.