I mostly order bikinis from zaful and I LOVE them. You can't beat the price. Especially if you're like me and have tons of bikinis not just one or two staples.
There was one time when they sent me the wrong size. I emailed Zaful right away and they sent me the correct size and asked me to donate the other bikini! Super nice!
Only downside is how long it can take for customer service to get back to you due to the time difference but it is usually within 24hrs. It's just that by the time I respond they are probably sleeping. Also the shipping obviously takes longer than somewhere like Amazon but I've always gotten my stuff in about a week- a week and a half.