woocommerce multy currency does not working

I can not use this plugin because does not calculate corectly the price using the conversion prices even if I have set 0.96Eur for 1 USD the value remain the same on checkout if I change the delivery country it is changing only the currency but the value remain the same. Also if I activate Sync checkout currency the check out page it is refreshing continously and can not make the check out. also if I have set a different currency in my website other than the default currency and try to checkout the checkout page is refreshing continously and can not make the checkout. How can I solve this??????