Kixify.com is a good website if you purchase from 95% or above sellers with a checkmark. I've seen the negative reviews and it's based upon people buying from sketchy sellers with no feedback and selling $199 Travis Scott shoes. John was right about the common sense. Kicksonfire app is the place you also want to buy because that has the best sellers and most reputable on the platform.
If you need help: email kixify kicksonfire. Also reach out to sellers email. If you file a chargeback for no reason you're making the processing 15 times more difficult. A simple ask or email helps.
Shipping times are usually 3 to 15 days. More in the middle. Items come from the USA or Europe and sometimes asia.
All negative reviews seem to be blaming the system type of people instead of self accountability as in doing your homework before purchasing.