problem when uninstalling Ad Injection

Hi all,

I am using WordPress 4.6.3 with the thème OptimizePress.

I was testing “Ad Injection” by adding a Get response form (script) in the field “Bottom ad (below the post content)” of Ad Injection in order to display the form at the bottom of all my aricles. I did not manage to do what I wanted (form apears in different location of my page in stead of only at the bottom of articles) and decided to uninstall the plugin by:
– deactivating the plugin and deleting it from the WordPress plugins control panel.

But the form I had injected still apear after this uninstallation. Could you help me get rid of them?

I have tryed to re install the plugin in order to see if i could still acces the code I had put in the field “Bottom ad (below the post content)” to delete it but it no longer appears.

I have deleted all cach with “WP Super Cache” but it still is the same.

Any help to solve this issue would be highly appreciated.
Nicolas