Added sugar instead of syrup to sorbet mixture
One problem is the amount of sugar, and to adjust for that the specifics of your sugar syrup would matter (how much water to how much sugar, and is that by weight or volume?)

From there, you could add enough additional juice, vodka and water to regain the proportions, and then it's a problem of dissolving the sugar (which is not being helped by being kept in the freezer while you figure out what to do.)

Running it in a blender or putting it in a mixer with a whisk are typical ways to deal with the dissolving problem, as is warming it up, though you may not want to simmer it as that will affect the vodka and possibly the flavor.

The simplest resolution might be to admit the error and ask your boss what they would like you to do - screw-ups happen, and it might be better to toss the ingredients (or pay for them and take them home to try your salvage operation on) than to try and save them and end up serving inferior product. Generally the cost of ingredients is a small fraction of the price of the product served, and serving a bad batch might have a long-lasting negative impact on anyone who got that batch.