Raj N.

I have had both positive and negative experiences of buying products from Swappa. If the seller is honest then you have a good experience. I have had several such experiences. Most of the sellers do work with the buyer to make it a good transaction.
But, if the seller is not then you are pretty much on your own. I have had a few of that as well. In such cases, Swappa doesn't get involved in resolving the issue. They will direct you to PayPal to find a resolution. That process is tedious and time-consuming. Their resolution tends to be to find a way to void the sale. Sometimes it is possible but sometimes it is not. Tread with caution when buying from Swappa. Ask the seller all the questions.

To answer your question:
Ways you as a buyer can protect:
Make sure the seller posts pictures. Battery health is one example. One seller refused to post a picture but claimed all along that the health is good. It turned out to be false when I got the phone. The seller refused to cooperate to get the battery fixed. Swappa doesn't do anything in such situations to resolve the issue even though there is enough proof to show that the seller was dishonest. Swappa recommends resolving such issues via PayPal. Involving PayPal is a long drawn out process and their decision is usually to return the device back to the seller and void the sale.

Another issue I had was with the screen. The touchscreen was not working. The seller claimed that it is working and there was no issue. Thankfully, the seller was good enough to take it back and refund the money.

What I always do is to take the Apple devices to an Apple store and have them do a free courtesy check. That has always been very helpful. Both the above issues were identified through Apple's courtesy check.