Rebuy and any other electronics companies buying used products can usually be SE'd easily.
This is for Germany.
1. Go to Rebuy.de and choose a product you want to "sell" below 500€
2. Fill out your info and bank account or PayPal and wait for the confirmation email with the prepaid label to send them the product.
3. FTID them (opt. 3 preferably) and wait a couple weeks before contacting them (at least two)
4. Act frustrated, say you want your money and it feels like they have stolen from you.
5. Find an IMEI of your product online along with a serial number because they most likely will be asking for them in an email.
7. Give them the info when asked for and if they ask for a receipt, say it was a present.
8. You'll get your money within one week.
Have fun