A warranty or guarantee ensures that the seller stands behind their product. If anything goes wrong with the phone, like technical issues or battery problems, you have the right to return or exchange it. Platforms like Facebook Marketplace or Gumtree rarely offer these protections, meaning you’re on your own if something goes wrong. Certified sellers, like We Buy Phones, provide warranties and guarantees that give you peace of mind, knowing you’re covered if the phone isn’t up to standard.