Uniqlo complaint: very bad customer service and missing Item

My wife and I love your shop (normally) and went to buy gifts and personal stuff in Brussels as we were passing for one day as tourists.
we got 10 items and when paying at the cashier I noticed the employee passing one item twice.
after telling her, she replied that it is impossible since the system wont allow it, we took it in good faith and paid after i counted that it was really 10 items on the bill and left.
on our way out the alarm rang and we had to go back to the cashier
issue number 1: one item was counted twice ( as we told her)
issue number 2: another item cheaper by 50 euros was not counted

she reversed the transaction and did a reimbursement to the 50 euros, to be returned to my credit card.
issue number 3: when I reminded her that i told her this, she told us we are becoming annoying customers and that we don’t know her job !

we left the place with a bad experience in mind, but at night while doing our luggage’s ( store had closed) we realized that the item that she counted twice was missing !!!

we basically got ripped twice for the same item.
we travelled next day in the morning

as per the ticket the person serving us is : Marta
it happened on the 25112021 at 18:32 store : 303