How do I use Female Engineering’s trial guarantee? We offer a 45-day trial guarantee starting from the day you receive your period underwear. During this period, you can try and use the product. Want to use the guarantee? Here’s what to do: Contact our customer service and provide the following: Order number or store receipt Article number Reason for the return Once we’ve received your information, we’ll assist you further. The refund will be processed within 14 days. You don’t need to return the product — you get to keep it. The guarantee applies to your first purchase of one (1) Female Engineering product. Related articles How do I make a return? What’s the cost for returning an item? General Terms and Conditions How do I return items in a package offer, for example “3 for 2”? How long do I have to return an item?