Similar story to everyone else. Received a faulty product, and was referred to the "seller" who would not accept a return unless the product (large set of garden furniture) was packaged in a suitably sized box which met the specifications of the original box - obviously an impossible request!
ManoMano actually have a process to deal with this called a "Concrete Guarantee" which they have hidden away in their terms and conditions. When you request this is opened, they refuse and refer you back to the seller. They then refuse to answer any more questions. I am reporting them to trading standards, and can only urge everyone else to do the same as from reading the reviews they are regularly in breach of the statutory rights.