OP - Honestly - what do you expect?
It's ASDA (the UK name for WalMart) and they care not a jot for you.
You are a cash cow to them (like all of their customers) and while you think you might be important to them - you are NOT because they keep on telling the whole world they are CHEAP - and that is exactly what they are. If you stop shopping there they won't care (unless we all do it)...
Cheap meat from Romania, cheap grain from Russia to make the bread (which feels like it might float upward if you don't tie it down), cheap bags which break before you've made it to the car, cheap Polish milk, cheap "fresh" fish which is always three days old and NEVER, EVER sourced from British fleets, cheap staff who have to "qualify" for minimum wage, cheap T-Shirts which are made by VERY cheap labour in Pakistani factories (we all know those stories and they're all true...)
So what do you expect when you give this company, this global conglomerate your money? Do you expect that they will treat you as someone they care about - they DON'T care about you - and they never will. It's not Fortnums and it's not your local butcher / baker or grocer. They have ZERO investment in you as a loyal customer and that is how that model works.
You will never get "service" from a conglomerate who views you as a digit, a factor, a unit. Asda is just the UK face of WalMart who will always put on sale and provide the cheapest, lowest grade, worst possible goods they can con you into buying for sixpence less than any competitor.
Don't be fooled.
Don't join in.
Don't be Homer Simpson.