I made this mistake too... and although I do (honestly...) take it on the chin, I have been really disappointed with Samsung's response. I contacted them via the Chat feature in store. I was 'upgrading' my S23 Ultra 512gb but on the evening I placed my order I was having issues selecting Samsung Finance at checkout. Makes sense in hindsight, as I has Samsung insurance in my basket (again, the irony)... and I assume this was why I couldn't check out, given that the insurance is funded via direct debit on an ongoing basis. On my 4th attempt of restarting the purchase, going through the trade-in details, entering all of the (gratefully received) discount codes from Samsung I finally managed to check out. I'm still convinced I selected the 512gb model as I took a screenshot (sent to Samsung) - but it was taken during the ordering process not at checkout, so can't be verified. It wasn't until I realised via Smart Switch that the S25 Ultra had insufficient capacity to transfer my data across that it was the 256gb model (yes, I know it says so on the S/N sticker at the bottom of the box - will I check next time? Of course!).
I immediately contacted Samsung who have essentially (and let's be honest, almost certainly correctly) told me it's my own fault. But - hear me out - I'm not sure these issues are always so simple. I explained it was a very genuine mistake, if I did select the wrong varient - and why would I 'downgrade' my storage. Also, it doesn't make much sense as a consumer to pay for less... i.e. I have paid exactly the same as a customer who has received the 512gb phone. I think it's a poor customer experience for Samsung not to check (an automated response, during checkout... I don't expect a human to call me). Let's be honest, Samsung could just choose to send out the larger storage varient to all customers purchasing during the promo period... I assume they don't to save money (I literally cannot think of one reason a person would intentially choose to pay the same for less). Crikey... very often in a grocery store the person doing my checkout will flag and BOGOF offers I have missed... and when I shop for groceries online apps flag offers not fulfilled so you have chance to rectify if you wish). A promo code would have been easier. Anyhow. I politely explained that I was an early adopter and very brand loyal (purchased lots of watches, currently wearing Watch7) and am fully integrared into the ecosystem... 5 TVs at home, soundbars, every Galaxy phone since S2 over a decade ago. At first they DID offer to send out the 512gb model for £5.99 postage (fine) and took my details. But then.... the chat went silent. After several minutes they came back and said they'd only refund and exchange if I accepted a 30% penalty as I had used the phone in my possession. Anyhow... you get the idea. Sorry for long message but I feel better for moaning. It may have been my fault (I will never know 100%)... but as it was a genuine mistake, as I paid for the phone... could they really not just put it right? I was actually pretty surprised by their refusal to help or meet me half way. The End.