Another battle with the self serve at M&S. This time the Simply Food where the gift voucher on the mobile app did scan but only after the attendance of two staff to resolve a non credited sparks 50p voucher. The first one was not authorised to credit so I had to go through the whole thing again with the second. Then, after "paying", the receipt got jammed. Hello to staff member 1 again who then failed to manage to open the paper holder and had to call on another, different, colleague. Crucial thing was there's £7.59 left on the gift card.