Poor service - treated worse than a ********

I keep on receiving poor service repeatedly from builders warehouse. On the 1st week of April I took my machine trim 4300 to the store as I was experiencing problems after few times of being used. When I got to the store I explained that the machine stopped working and when I closely looked at it the petrol seemed to be leaking as if the tank was not sealing well. They took the machine and said they will take it to their workshop. After 2 weeks they called and said the machine was not working because of my fault, I mixed the oil and petrol wrongly. However, I explained to them that I never did that, beside the nature of my work has exposed me to different kinds of machines, and I followed the instructions as I was given when I bought it. I know the importance of following the instructions. I then reported the matter to the head office. Had been communicating to Mr John Hammond, after waiting few days to get the solution he said was my fault that the machine was not working. I need to pay for the repairs or take the matter further if I want. I cannot explain what kind of service or response is that to the customer! He then proceeded to say I can go and collect my machine from the store. Due to the nature of my work I could not go same day. I went to the store for the collection of my machine after 11 days (10/05/24). When I got there I was told by the lady assisting at the refund side that my machine is not there. I still do not understand what kind of treatment is this from such a big brand as builders warehouse. Worse now even driving up and down for nothing. Maybe that too is my fault.