every product in our store has a sale tax of 21% that i should pay later to DGI.

this tax is included in product price.

we use the odoo Point of sale for sales.

When the customer pays for the products if we receive cash we issue a receipt and when pays with credit or debit card we issue an invoice. when issuing the receipt is possible to remove every product taxes or tax the product to 0%, the product price is the same, with taxes or without them.  the taxes is not printed in receipts. 

when i go to accounting to check how many tax i shoud pay to goverment, I should see only the taxes invoiced. or non invoiced with 0% tax

for example:
 if a customer buys one coca cola at 3000 pesos, this coca cola has included a 21% vat of 520.66
when the customer pays the 3000 pesos in cash. this tax is removed or changed to 0. the total sale was 3000. (the price is not changed)

we printed an receipt

if another customers buys another coca cola (same product) at 3000 pesos with the same included 21% vat of 520.66 but this time, he pays with a credit card. the customers pays the 3000 pesos, and we issue an invoice for 3000. 

in acounting reports, i should pay to goverment 520.66 of vat not 1041,32 

How I should do this?

thanks you!!!!!