Don't believe what you read in the advert - read the Terms and Conditions
1. The flosser is claimed to work faster and better than manual flossing and to reach between tight gaps - it doesn't.
2. Instructions are a poor translation.
3. They advertise 30 day money back guarantee and say in the advert "Returns
We have a 30-day happiness guarantee, which means you have 30 days after receiving your item to request a return. If you are not happy with your purchase for any reason, please let us know and we will aim to rectify it as soon as possible."
Note "for any reason" But refuse to do so unless it has not been opened or used. Why anyone would keep it for 30 days untested is beyond me, and how can you test it without opening it?.
4. They have a supposed summary of reviews by over 400 people, yet many of these reviews are word for word identical within, say, the 4 star category and even between the 4 star, 3 star and 2 star categories