A very very complicated commercial service! After ...

A very very complicated commercial service! After making 330 euros of purchases for the first time at decathlon rather than at my usual supplier for a gift, the seller on the shelf advises me to make a ticket without price in case of exchange and assures me that the items can be exchanged although on sale because I am hesitant on a model. When I arrive at the cash register, I ask the cashier to register in the loyalty account base so that I can take advantage of points when making this purchase and print out a ticket without price. When I carried out the financial transaction by credit card, the seller announces to me that my loyalty card has been registered after the transaction so I do not benefit from any points, that the tickets without purchases do not exist and that my articles cannot be resumed ...