About my sainsburys delivery?

[Rainydaize]

Sainsburys cancelled my delivery yesterday. In there was food for mother's day and lots and lots of wine. Apparently due to IT issues they have cancelled over 200 orders.
The wine I ordered had 25% off yesterday. They were happy to reschedule my delivery for tomorrow but would not honour the 25% discount on the wine which ended yesterday.
After an hour on the phone, being passed from pillar to post and trying to work out how to reschedule my order, I then was told by their online person they would honour the discount.
Today my order has been cancelled again and now they aren't going to honour any discounts, basically it's tough.

AIBU or is this dreadful customer service?!

I haven’t had issues with their deliveries but a few weeks ago I had to freeze my debit card due to security issues with my bank . I updated my card with sainsburys using another bank account as they were unable to take the money. Due to a delay with my new. Visa card arriving , my next 3 deliveries were paid for via my alternative bank. Suddenly £70 was taken from my original bank last week . Confusingly I was awaiting a delivery from Sainsburys on the new account that day . Customer services were not very helpful . My bank informed me that the £70 was for the shopping 6 weeks ago at the time of my security issue. It was annoying I was not informed that they were going to do this . I was not aware that they even could , given that I had updated with new bank details. I probably wasn’t as on top of things as I should have been due to illness but felt that customer services wouldn’t let me speak and just kept referring to the delivery expected that day . Obviously I would have called them had a realised I had not paid for the order .

I’ve been using Sainsbugs delivery service for a year now, and it’s wonderful. They hardly ever substitute anything, and when they do it’s a superior replacement. (I’ve had organic grass fed meat instead of standard, at the same price, for example). The drivers are always polite and we have a nice chat while I unpack. The only cancelled delivery was during a blizzard, when the entire bus service was also cancelled for my area of Scotland, so understandable.
I find them much better than Waitrose, who had multiple substitutions and very poor quality wilted vegetables when I tried them.