I Have bought from this company multiple times and you always get what you pay for. This company deals with used devices so its understandable if a phone is sent out and ends up being defective, but they have stood by their products even if one or two devices needed to be returned.
You do pay for return shipping, but they are quick to give you store credit or an exchange in my experience.
My company has sold many of their devices over a couple years and we have not had any customer complaints. I would recommend this company to anyone in a re-sale business.