riikka_gg I know that the new vouchers have been tested and £50, £30 and £25 vouchers have been redeemed successfully this month
I've referred a couple of cases where £50 vouchers failed to @dez_d who has been investigating and was having discussions with staff concerned, so you should probably tie up with him.
Offhand I don't remember whether these were the same members that have been mentioned in this thread, but it did not help that the £50 vouchers had not been pre-announced and we initially suspected that these were not giffgaff or o2 vouchers.
Just a guess, but you will remember that there were some problems buying goodybags a few days ago. I'm thinking that maybe system software had to be rolled back to reinstate working order -- which might have inadvertantly undone the ability to cash larger vouchers.