Beware the guarantee !!!

Ok, I left a review on here after having my bathroom fitted, it was very positive as our fitters were great and worked very hard to fit a bathroom specifically designed for our disabled son. I was happy with the designer and assured by the guarantee, which kind of made me think it would be worth paying the extra. Not even two years in and my shower has broken twice! The first time it was fixed and I was happy. This time customer service tell me the guarantee is not for 'anything that moves or swivels!' And they want to charge £50 for fitting a small valve! Frankly not happy! The website is therefore giving miss information as do the sales people. What in a bathroom that's expensive doesn't move? I have said I'm not happy with the shower as it seems to have a fault, left messages but guess what, no reply! I think that a new shower to replace one that is clearly faulty ( on /off starting to 'go' as well) is not unreasonable. My son cannot tolerate the faster section of the shower due to his disability and the lack of response is making life even more difficult than usual. I expect more from a company that goes by the tesco name and charges a premium for peace of mind that doesn't exist!