Ryobi Polishing machine

i purchased a Ryobi machine from builders express in ballito, i spoke to the manager named Lolly date 30/05/2015 i told him i want to start a new service at a car wash to buff vehicles. i used the machine for the first time and the electronic switch stopped working. i took it back to them and they said it was because of a faulty switch, they didnt have any more of the same machines so it had to go for repairs. they then contacted me saying the armiture and brushes were burnt and i had to pay for the repairs, i told them that it was impossible as i only used it only for half a car and i have video footage to prove it. i then contacted mass discounters who seemed very helpful but were only willing to repair it for free for me. i told them i do not want this brand anymore, i have since bought a stramm machine for half the price and done over 20 cars with it and its still running strong. i want a full refund so i can buy a different branded machine, but their answer is its my fault. this is what you call inferior quality and product misrepresentation. Ryobis products are useless and so is the service by mass discounters. i need someone in higher authority to contact and resolve this!