We were in full quarantine for two weeks at the end of March and for the entire period (Mar. 21 - April 4) there wasn't one single insta-cart slot for either pick-up or delivery through any SuperStore in the city.

I'd never used it before so I don't know how popular or efficient it was but the system is chaos now.
I placed a small order on Monday for some pharmacy stuff that I couldn't find elsewhere and had to choose delivery to get a slot (nothing available for weeks for pick-up). They ended up changing the time 5 times and it finally resulted in me having to make a flying trip from home to my office (the delivery location I specified) last night at 6:45 to meet them and get my stuff. I won't be using the service again.