WooCommerce Multi Currency plugin isn’t working properly on my website

The plugin isn’t working well on my website; it does not convert the currencies accurately and the currency symbol does not even change – it kind of retains the default currency symbol even when other currencies were selected. Now even the new update kind of keep shrinking my website, and at the footer area it display a message that there has been a critical error on this website. This plugin isn’t just working for me at all and I couldn’t use it since I purchased it. I already requested for refund and was instructed to open a ticket for this. This is becoming annoyingly frustration and I want it fixed ASAP, else I want my damn refund. Thank you.