Bad Hairdressing

first appointment was on the 28th Feb, I asked for a certain look did supply pictures but he did something different which damaged my hair badly so he asked that I buy an expensive treatment afterwards, I went back on the 13th March so that he can fix the colour and cut it even, the colour is till not right and my hair is cut badly. the people at my work also notice it and said I should sue the hairdresser that worked on my hair. I would like to be refunded at least half of what I have paid, so that I can get it fixed at another salon.