Well i just signed up and i don't know what that service is
Provide me more details and i will consider it
Buyers send BTC to me, I hold them until the buyer claims the item is in their possession, then release the coins.
If buyer claims item hasn't arrived (or if you claim the item's shipped and it's time to release the coins), you need to provide evidence (a tracking number, for example) the item was shipped.
If there is still dispute after that, then I mediate between the two of you, and whoever has the most convincing evidence wins.
This protects the buyer from scammers and gives those buyers confidence that the seller is not a scammer, thereby allowing you those customers who would otherwise pass.