On arriving at Aldi shop in Airdrie checkout I removed my used Aldi carrier bag, which by the way was all crumpled up from my pocket in front of the checkout girl so she could acknowledge I had not purchased it new, obviously an old bag. When all items were scanned she did not issue me with a receipt as requested before I paid, after payment she asked me twice to touch my bank card again to machine before I finally got my receipt, in total I had to use contactless three times to obtain my receipt which I thought was a bit off. When I got home I noticed she had charged me 20 pence for a carrier bag that I did not purchase and thought this strange as she did not even scan my own carrier bag. I would advise anyone shopping at Aldi not to use an Aldi carrier bag, why was this allowed to happen. Not a lot of money but then again its my money. .