When I pickup my order, I call them and tell them to use my PC optimum points for payment. Sometime, they do the bill before we pickup the order, we better inform them in the special instructions when ordering.
https://www.loblaws.ca/faq#faq=3kKssa6Sybe39VaUwvtF1JCan I redeem PC Optimum points to pay for my order?
PC Optimum Points can be redeemed when picking up your order. Please inform the concierge when you arrive and have your card or device ready.