Only once. November month. On my primary Amazon account I loaded Amazon wallet with GV equivalent to 30k using my one of my two credit cards. I know I can't load more because of the rules. So created another account with another number where I tried adding the second credit card for buying more GV's as gift to be sent to my primary account but each time I add a GV and try to buy using my 2nd credit card, I couldn't. I tried with my friend's card too. I just couldn't. But I was able to buy an amazon product using any credit card just not the voucher. Strange.