Cannot completely delete

I turned to the plugin’s community support forum some time ago but no reply so far.

The thing is, I wanted to delete this plugin (even though, it’s very good, I don’t need it). The deletion of this plugin works fine except, it does not delete the 15 databases, it set when installed and activated. I discovered that there was an option “Keep historical tables” in the system settings saying “Check this if you want to keep historical tables after plugin deletion.” Logically, the other way around, when unchecked (and saved), the databases should be removed upon deletion of the plugin? It does not work this way though and the databases are still there.

Is there an other way to get rid also of the databases or how to proceed? I’m running a Worpress site in a .com (not .org) environment and therefore can not manually delete databases in the host server. So, I must rely on the built-in function of the plugin to do that when unsinstalled / deleted.