Sainsbury's gift card conversion to coupon bug

7rebor

I regularly convert a £400 Sainsbury's gift card to coupons on my grocery account because I get 5% off the gift cards with my work scheme. 

I've always been suspicious that I'm missing coupons here and there and not realising. 

A few months ago, I finally decided to check, I added up the coupons and it was only £330, £70 missing! 

I called up Sainsbury's gift card team about this and the woman was perplexed. She kept repeating that you can't spend two coupons of the same value on a single shop, but I have done that so many times it is not true. Then she got confused and went away to presumably talk to a manager. 

When she came back, she said that THEY can see all my coupons, but they don't appear in my grocery account. 

Knowing this, she emailed me the coupon codes. 

You can enter the codes in the coupon section of the grocery account, but they won't add. I thought maybe this is because I have coupons of the same value, what she was trying to explain to me. But I still can't access my coupons. 

I know Sainsbury's will sort this for me, but what the actual f? If I wasn't paying attention I could have lost tons of money and negated the reason to use coupons at all. 

I hope Sainsbury's rectify this and other bugs with their system. It's really hurting the consumer!