@vinaysingh0399,
Indexlabels gets positioned based on the value coordinate and seems to be working fine. Having a JSFiddle along with the chart options and the data that you are using will help us understand the actual scenario better and guide you with an appropriate solution.
From what we have observed, sometimes things get delayed mostly when we are not able to reproduce the issue or not able to understand the exact requirements.
Having a JSFiddle helps us in figuring out the issue and many a times we can just edit your code on JSFiddle to fix the issue right-away.
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Manoj Mohan
Team CanvasJS