the data points on the graph are not plotted, even though the header of the csv file can be shown, i think somewhere in my code its not able to read the data

There seems to be something with your data transformation where NA are introduced. ggplot remove those NAs before plotting. This could explain why you can"t see any points if all are NAs.

Did you test all this workflow outside of a shinyapp ? I would do it: Load the file, do the transformation, see how it goes and try to plot.

Without a data sample to help, and better a reprex, it is not easy to help you. If you can, please provide one. Thank you.