Bit more info here and in some other threads, but the tl;dr is that Visa/Mastercard/etc. often have stipulations on how/where their GC's can be used, particularly regarding physical locations. In general we do not suggest using 3rd party GC's for this reason, since they will often simply not work.
We don't process or handle payments on our end (that all happens through our payment brokers such as Epoch/Verotel/etc.), so there's not much we can do directly regarding this unfortunately, though I believe there's been some discussion on this internally as far as possible workarounds/etc.
