The author can work on correcting the error you sent, perhaps the delay is due to Christmas, I can not be completely sure, also the author can create content alone, sometimes it can be a complex process, in any case, wait for a response from the author
I didnt edit CSS. What i’m not sure of is if switching to another theme, then back to this caused the issue. While I noticed this after we did this, I cannot say with certainty that it was working perfectly before.
It could be that changing it and then coming back may have caused something to break although it looks like the issue with your website is mostly CSS related (it’s the articles spilling over wide on the lower part of the page right?).
the item was updated in Jan 2019 so if you are using a version older than that then you probably wat to update it (download the latest copy from your downloads page on themeforest)
Beyond that without spending some time looking into it then it’s hard to advise on what may be causing the issue, however over 6 months there is no obligation for the author to assist
you coud probably find a freelancer on www.studio.envato.com to put things right otherwise