If you have your reciept or another method of proving you bought an item from a retailer (bank statement usually), and you are still within warranty period then your consumer rights entitle you to a full refund of money or a replacement (as long as the fault cannot be attributed to abuse of the item by you or incorrect care).
Even if you are outside of a 12 month warranty but can prove that the boots were hardly used in that time you can still claim that they were unfit for purpose (wear on tread is usual proof).
Read the Consumer advice website, call their helpline and get them involved in your case.
Have had a pair of Mirage but didn't buy GSB crampons as I didn't want the problem of frozen, compacted grit filling the hole. The toe pad wore down quickly and the hole became exposed. Eventually got a refund because they weren't waterproof. Had 2 pairs of Charmoz fail on waterproofness too. (1 pair failed after 3 days). Gore Tex doesn't work in boots - you're grinding grit and dust into the liner - imagine putting your gore tex jacket into your boot and walking on it for a few days.
Rumour is that Scarpa had discontinued the GSB feature - I hope you got your pair in a sell off.
Don't buy GSB crampons as you won't be able to use GSB on other boots that you might buy.
I've not had problems with the MB company but I've had to send 3 pairs of Scarpa Charmoz boots back. One pair gave me wet feet after 3 days - they offered me a refund on a 3 occasions without question. The problem was with the boots, I still buy Scarpa but don't buy fabric boots or believe Gore Tex works in boots
Thanks for having another look at the OP and seeing it differently, as my other posts have made clear, I appreciate honesty.
I've had a look at it too and although his first post still didn't give me the impression that he'd recognised that they should have just turned back at the first sign that the route was iced up, I'm relieved by the honesty and clarity of thought in his subsequest posts. I've definitely been in all the compromising situations he's described, friends, tools, conditions, dehydration. I'm sorry I came across as 'berating', as I only want to be sure he'd come away from the situation having learnt the most important safety points I've learnt from those situations. Please understand, I've been out a lot this season and seen too many MR recoveries or bad practice, I'd just come back from another alarming week on the fells in the Lakes on Fri when I first posted, I shouldn't have bothered posting.