I used the app for about 1 month to make it works perfectly with my site but the app is not goes great with other apps and the support here is not helps at all they only say - this is the app and that's all. by the way they didn't gave me more days of trial to test app - so enjoy the 4USD guys.
It doesn't work well.. It works for some products and other don't and then it doesnt work for the products that it used to work but works for other. I do not recommend this app.
Did not work with currency conversions only in USD, then when uninstalled due to setting change it removed all product prices.
if you need i will check your issue and make it work for you.
Reason why you had hide prices after app uninstallation should be only because of your theme CSS.
I can check it for you too.