nectar points mix up query

[bogle]

Hello all and sorry if this is the wrong place but I'm v confused about nectar points.

Basically what's muddling me is the amount "nectar qualifying spend" at the top of the receipt and then the "value at sainsbos" below. I had about £80 quid on the top amount, spent £40 in Argos purely on points then went straight to sainsbos to do a shop, thought i had a few quid left on card so handed it over and asked to use those points and cashier said I had £32.50 left, I was quite surprised but in a nice way, and just thought that the top amount on the receipt must be correct.

This weekend got an online nectar statement and it said I had -5166 points, has anyone else ever had minus points?

not sure but at argos you have to spend in mutliples of £2.50, so if you were buying something for £11 they would take £10 off and you pay the difference or they would take £12.50 off and give you the £1.50 change on an argos giftcard, as far as I am aware at sainsbos if you had £21.54 in points you could spend £21.54, dont know if that hekps in any way! I find the online statements can take time to update.