I'm pretty sure I payed double for a meal and 2 be...

I'm pretty sure I payed double for a meal and 2 beers I used a gift card and cash when the server came back he said I only owed 6 and change then asked for a 20%tip on my total, then the server came back saying I owed $22 still but they couldn't give me a receipt saying what my card covered and what I still owe. There was no understanding of what I payed for, having said all that the burger was pretty good