First of all: your top looks gorgeous. The soft pink is beautiful and your stitches are perfect. I visited the pattern site and understand that you wanted a different neckline, but I have to admit, that yours is much nicer (in my eyes) and more practical in summer. I guess you will wear a sleeveless top in summer?
Sadly, I am not sure what happened with the neckline, but I also guess that you knitted not enough rows of ribbing. And when I look through the other projects I see many, who also did not achieve the turtleneck style. The one project which looks nearly as in the pattern picture shows the top on a dressform.
https://www.ravelry.com/patterns/library/ella-3/people
And here the top sits much higher up under the armpits, so that the neckline is also higher on the neck. But its a dress form not a human... therefore I think it is also a problem of general proportions, not only the length of the turtleneck. Perhaps your top stretches too much over the bust area and/or you need a smaller neckline combined with shorter raglan lines (I mean the cable part).... But it is more likely I fantasise without a real clue. Sorry... perhaps @shanibeer can help