1 year warranty *******!!!

I purchased a Valeo clutch kit on the 10-03-2018 for my Runx RSI which has a 1 year warranty. After I fitted the clutch my car had a shudder when I pull away. However I thought maybe that the clutch should be driven in but I was wrong because it just got worse, especially when the car is cold. On the 04-08-2018 I took out the Clutch because it started to irritate me. Upon arrival at Alert engine parts in Ottery, the store Manager told me that they will NOT exchange my clutch. He said the Clutch was probably fitted wrong or I drove with my foot on the clutch. I then argued with him because this is my 1st time after 8 years of having my car I changed my clutch and this is the results. I went home to get my gearbox and fork to show the Store manager and he told me that my shaft on my gearbox has a ridge on and that it could also be the cause of the car shuddering. I told him that I could purchase another clutch at the store but if this is the type of service you get then I’ll purchase it elsewhere and bring my car to the store with my same gearbox that’s supposedly the cause to prove him wrong. I then purchased a new clutch at a other store and fitted it into the vehicle. My car then had no problems . On Monday 06-08-2018 I went to the store with my car and told the manager that my car is fitted with a other clutch and there is no problems, and he could not answer me. I asked him how do you know that the clutch you sold me wasn’t a faulty one, and he said it can’t be. Alert then sent my clutch to Valeo to be inspected and the Rep Mike van Staden told me telephonically the exact same story as the store manager told me. I also asked Mike how does he know that the clutch I purchased wasn’t faulty and he could not answer me. They are trying to blame everything else besides the clutch. What is the use of the 1 year warranty?? Please beware people, they are *******s!!!!!!