Sliver hair turned to white/blonde 2 days after dyeing

I'm a 17 yo male that never attempted changing his hair colour. Went to hair stylist, knew what colour I wanted (basically silver as far as I know colours, I asked initially for platinum) Naturally I have dark blonde hair. They bleached it and then applied the silver "dye", did my hairstyle. It was great. For approximately 2 days. Now, I don't know whether it is my fault or the person dyeing my hair or what. I clearly remembered asking "will it be okay, will the colour stick to me and not fade away instantly" in response I got confident "yes, it should dye very nicely with your hair" I haven't yet used the purple shampoo that they recommended me, it's day 6 after changing to silver and it's preeeetty clear it's turning blonde. I thought I was crazy, asked my mum about it, she confirmed that it's not silver anymore. I'm kinda devastated. I know it sounds like whining, but it kinda is. I payed with my own money, I went against my dad's wish, whatever, I was dead set on "I want to change something" About factors that could be my fault. On the night after the dyeing I washed my hair with water, no shampoo. After that I started using shampoo with hair conditioner on daily basis. I still haven't used that purple shampoo. And that's it as far as I think (oh I think about it all the time now lmao) Please, help or give advise about what can be done now to restore the colour. If nothing can be, any advices on how to maintain that beautiful silver colour? I will certainly dye it again after two months.