Problem in checkout page

I purchased the plugin for the option to change the currency at checkout, and I activated it, and the currency did change correctly in all websites except checkout page, but only on the front end for the customer. However, when the customer is redirected to the payment gateway, the amount is still requested in USD. As a result, the gateway continues to reject the orders because it’s only available for EGP payments.
For example orders with 1000egb appear in website 20$ and cart 20$ and checkout 1000egb it’s correct
But when redirect to payment getaway request 20$ i want request 1000egb