Author has published a graph but won't share their results table
There is no results table to go with the graph.

Use Datathief: https://datathief.org/
Despite the name, in most countries using Datathief is explicity allowed by copyright law.  Data cannot be copyrighted.

They also did not specify one of the parameters used to produce the results.

Two possibilities: it does not actually matter or peer review has failed.  When it is your turn to peer review, check for this type of mistake.  Sorry I cannot not help in this situation.
Paper authors can choose not to answer their email if they wish.