I Hope I can add some info to this thread
I bank with Bank of Scotland (Halifax) which is now owned by Llyods
I have 2 gg Sims (actually 3 but only use one occassionally) which until a few months ago I could top up / buy Goody Bags with online.
2 months ago I bought a gb for sim 1 using my Credit card and all went through fine
I then preceeded to buy one for sim 2. This was declined by the bank according to the message displayed by Giffgaff
I thought OK the bank is seeing it being used for 2 phones and might of rejected it, not having time to mess around I paid for the second one with my debit card and that went through (Other online payments with othe vendors using the credit card were however fine)
Last month exactly the same happened but again being short of time I bought one with the Credit card and one with the Debit card.
Today I needed to by another goody bag but decided that I wasn't using Sim 1 more than 20MB /day and would not buy a Goody bag for it. So I tried to buy a Goody bag for Sim 2 using my Credit card - Alas once again GiffGaff says declined by bank. So getting very annoyed now at the bank I phone them up and to be fair to them they did a full investigation and it is definately not being rejected by the Bank they could even give me the authorisation code that they gave GiffGaff for the payment. They were very helpful but assured me it is a GiffGaff issue and they have a very large number of callers with problems with GiffGaff.
I have tried removing the card and re-entering it. Strange how even when you are not trying to buy anything if you try to register the card with GiffGaff it tells you the Bank has declined the payment
GiffGaff you have some serious problems with your payment system, I've been with GiffGaff since their early days
I sent a message to an agent to try and sort it out but 2 hrs later no reply - so I have bought my last Goody Bag using my debit card to give me time to purchase 2 sims from 3
Time is to valuable to constantly messed around. Looking through the posts here it has been on going for months and it still isn't resolved!!