broke my site by changing all the price into USD

Can you please be more detailed about what exactly was broken?

можно на русском

After installing and activating plugin it changed all currency symbols ILS “?” to USD “$”

Of course! You should go to the plugin settings in this case, write ILC instead of EUR and set is as default currency! You did nothing after installing so you got default settings. Watch for one time this video please: https://www.youtube.com/watch?v=wUoM9EHjnYs to undertood it

More different info is here: https://currency-switcher.com/

And one moment – do not forget to set as welcome currency as ILC

Then for first time select currency on the site front by switcher to see that the prices are correct – from now all users will see ILC prices on their visit and will be able to change currency to USD if they will need

Also read: https://currency-switcher.com/everytime-i-go-to-checkout-and-then-back-to-homepage-the-currency-switches-back-to-default-currency/

Hello, please check, looks like your troubles in options only

So what is your answer?