Dining for Two Gift Voucher

Had a voucher that I had to use and decided to go there. Made a big mistake. Things were not explained well. Our voucher was for a 3 course meal for 2 including a drink. When we asked at the counter what drinks we could have we were told which ones so we ordered them. After having our dinner the guy gives us a bill for the drinks. We kept saying that we had checked with the person and he said it’s included in our voucher so why do we have to pay. He kept accepting that this was their fault as the person who was at the counter was new but also kept demanding that we pay for the drinks only because the drinks we choose was not from the voucher deal. This was really ridiculous as he kept arguing that we pay for the drinks even though it was his colleagues fault. Also the fish had more of batter and a tiny piece of actual fish which was so oily. Not happy at all with the taste of the food. Everything was deep fried and seemed very oily. I also had my 87 year old mother with me who has difficulty walking and she had to walk quite a distance to the pub because there is no parking at the pub.