LayerSlider Plug-in Update

I am running an ancient copy of LayerSlider v5.4 and had a problem with getting hacked so I am trying to get it updated to the latest version. I purchased support and am trying to enter my purchase code which is not activating with the following error…

You’ve reached the maximum number of authorized installations for this purchase code. Enter another purchase code or deauthorize sites before trying to add new ones.

This is the only site we have activated this on. Anyway to upgrade the plugin without losing my existing sliders?

The best way to get this answer is Contact your purchased Layer Slider Author.
Contact Author because Item Author are best expert about their Item functionality.

If you face problem with create ticket in Author support site then you can post comments using comments tab in the slider details page. Also you can provide screenshots of the issue.