Hi apputiwari,
If you are a commercial customer of RStudio, you of course have access to RStudio's commercial support.
In terms of support for free and open source RStudio, though RStudio-folks are generally not available for calls to support our open source products (we run a tight ship and just don't have the staff), this is a good forum to seek help.
The shiny team just put together the following: Shiny debugging and reprex guide. If the debugging steps don't help, post a shiny reprex (or the closest thing you can). That will make it easier for those who'd like to help to replicate your issue and offer advice on how to resolve it.
Having said that, in terms of the subscript out of bounds error, below is a general guide to that type of error.
But, at this point, I am not confident that guide will be helpful to you since I don't know enough about your particular error. What info would be helpful? check out the reprex of Shiny debugging and reprex guide