DeFacto Website Kept Giving Payment Errors Despite Trying Different Cards

I tried to shop on DeFacto's website, but despite several attempts throughout the day, I kept encountering an error at the final payment step. I reported the issue through the website's contact section, but they claimed there was no problem with their system and repeated the same troubleshooting steps I had already tried. Yes, I used three different cards. Yes, my credit limit was more than sufficient. Yes, I switched browsers and even tried the mobile app. Surprisingly, I was able to shop easily on other websites the same day without any issues. If completing a purchase takes this much effort and no real solution is offered, perhaps DeFacto should reconsider its approach to online sales.