Okies, in which case then I can only assume you have been caught up in the very small minority of customers for whom there may have been some kind of glitch somewhere in the system. Normally I would advise a call to Customer Services to try and resolve this, but you are certainly one and possibly two vouchers down now and that's not a helpful place to be, what with things as they are and winter well on the way.
What I'm going to do is pass this on to one of our fabulous Nexties to see if there is anything they can do to speed up the process for you. We're just a skeleton crew of volunteers here at the weekend who do what we can, but I'll give the lovely @Beki_EONNext
a shout for and ask her to pick up on this for you. I can't guarantee how quickly this will happen but I'm sure she'll take a look just as soon as she can. If I open a packet of Foxes Crinkle Crunch biscuits and put the kettle on, she'll likely happen by sooner rather than later. Hang in there, and we'll try to get you sorted👍