Issues with Checkout process

-- url of the page with the problem -- : www.fiestadeltamborpopular.com/
-- HikaShop version -- : 4.0.0
-- Joomla version -- : 3.8.8
-- PHP version -- : 7.0.27

Hi there,

We are having some issues with chekcout process in our website.

These are our settings:
- The main currency activated is EUR (€) because our Redsys TPV should be like this.
- We have enabled the HikaShop Currency Switcher Module because we want the user could change the currency they want to see the prices in our website (€ or $)
- Our product prices are in dollars (product configuation).

Our problem:

- When consumer wants to make the payment process, the checkout never appears and the user can't introduce the credit card information.
- However, he receive a mail and a code indicating the order has been made, but he never paid anything.

What we did:
- We unabled the switcher module and it actually works. The payment process appears and the client can introduce his information... but this could not be the definitive solution.


Solution:
How could we solve this issue? We would like our clients to be able to make the payment process completely, and even having the option to select in wich currency they want to see the products.

We hope you could help us with this. It is very urgent.

Thanks in advaced.

R&A