Shox Enduro Drone flies off

In January this year, I bought a Shox Enduro drone from Hi Fi Corporation The Glen. Since purchasing it, the drone has not been able to hover in one place without moving significantly left, right, forward or backwards. I then took it to a park to try and adjust the trim. At the park, one or more rotor blades would stop spinning. Eventually I lifted off with the drone and next minute the drone took off and flew away. It did not want to respond to the controller to return. It eventually crash landed in the property next door. I immediately returned it to the shop where I bought it. I was then contacted by a TEVO rep who advised it will be taken in for assessment. A few weeks later, the drone was returned and the result was dirty gears. I couldn't test it immediately and took it to a park on 02/03. On the first take off, the drone also just took off and flew about 300m, not responding to the controller and crash landed. I have witnesses that can confirm this. After that, the one white rotor blade also stopped working. When packing the drone away I checked all accessories and found that one of the spare rotor blades were damaged. I have not replaced any blades, so I want to know how the blade got damaged if it has never been replaced. I have also not heard good reviews of Shox drones from family who experienced similar events. I want to return my drone and have a refund of my money. One can't spend R1500 on something that won't work.