GrandmasueUK
Payment is only taken after delivery, because sometimes there are substitutions, so you wouldn't be charged twice. I often chop and change my order several times before delivery, so it's a good job they don't take payment every time. Hope this helps. Don't forget to continue to payment to make sure that things are added.
That's right.
I find Tesco the easiest site to use and the most helpful so far. If they have to substitute you get a refund of the price difference.
Waitrose ordering system threw me because they had several items unavailable but would not process my order until I cancelled them. Then it looked as if they still charged me for those items. I was ready to challenge them online.
Two days after delivery they sent another order confirmation which was correct.
Very confusing.