Big troubles

Hi, I downloaded “Polylang” yesterday. Since then my menu is not working properly and the blog page won’t accept a grid mode.
So I remove it but the menu is still not working.
Is there a better way to uninstall the plug in , what should I do to erase it totally?
I already restart everything even the laptop and reinstall Google Chrome, as there was no improvement I download the plugin again trying to find a solution but in vain…
It’s suppose to have a mega menu but it wont appear on my browser. Not even on another one.
I know the problem come from the plugin but I dont know how to fix it.
Thanks for your help.

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