CDKEYS Sims 4 Island Living $25

Hey guys! Has anyone used CDKeys before and can you walk me through the process? I typed in my card number three times and each time I hit enter it said the card was validated, but it brought me back to the checkout screen. No "Thanks for purchasing" screen. I've had a really rough week, and I'd just like to play. Has anyone ordered with them before? is there such a process? Just want to play my sims, dangit!