I wrote a rather lengthy reply to this last night, then my battery went flat and I lost it all. 
The gist of it was that the problem I had with the code was resolved when the online chat person sent me a link. Thank you for the warning about the charges, I checked my credit card and nothing has been taken. Have you contacted eBay? Because in effect the vouchers didn't work. Might be worth a try.
No, it was too long after the event. To be clear, I wasn't subscribing at the time, so it was entering the voucher code that triggered renewed access, and the code was acknowledged and accepted in exactly the same way as the code I had with my first Now TV package. It wasn't until a few months later that I noticed they were charging my card every month.
I had lengthy conversations with their customer service people who did seem to be trying to resolve it, but ultimately they refused to refund, claiming there was no record of those vouchers, and there was nothing I could do about it. If only I had taken those screenshots.