Issue on Nintendo Switch after full reset. These controllers don't pair and the touchscreen doesn't work

My son's Joy Con controllers are broken on the left side. I bought these new Joy Cons. I tried all the You Tube clips and it wouldn't let me disconnect the other controller on the right side. I have followed many step by step guides. I also took it to the Cex store. .I was told a full reset might work.My sons games are all store bought so I just have to download Fortnight and Minecraft.How is this frozen solution fixed please?

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