Duplicate posts

Hi,
I am using this plugin for long time, and I have spend days trying to fix problem with ducplicate posts. It seems cron runs that import twice. Even when I added condition on title, to prevent plugin to insert article with same title, it often does import twice. The reason is, cron runs that plugin twice at the same time. Those imports are paralel. No condition can fix it. Where is the problem? I checked cron and it has only 1 cron job. Please fix this, please, It is killing me. I need to check my site every few hours to delete those posts. I want to have some free time. I have no other RSS plugin, only yours. I deleted all plugins with con jobs, manually deleted that cron job from and reinstall the plugin. Still the problem persist. And I do not want to fix it with some other plugin deleting duplicate posts. I have lot of visitors and it is making my site lame:(

https://ww.wp.xz.cn/plugins/rss-post-importer/