Guaranteed food orders?

[Phase2]

Hi so I know everyday supermarket deliveries aren't guaranteed and you may not get everything.
But I've previously don't the food order that you can only collect from marks and it wasn't guaranteed - are there any shops that guarantee they will supply the items you've ordered and paid for?
Thank you

Oh that's really helpful about Waitrose and @Conqueeftador thank you , I will do the potatoes ahead and I hope your Christmas is lovely too

I always pre order from M&S to pick up early morning and on same day have my Ocado order arrive (mix of Christmas food and normal). Luckily before I head out to pick up my M&S order I get the text from Ocado listing any missing items, so can then pick up substitutes while at M&S.
I have so far had no issues with the major items in both my orders over the years