Eat it or leave it

In April they had a very good burger special running on Thursdays. On the 25th of April (Thursday) me and my husband went for the burger special, because the special was only running until end of April. When we wanted to order, we were informed that the special was not on that day, only in the next month again. So we left, and 2 other couples sitting accross from us had exactly the same experience. Now they have the same special running in July but on Tuesdays. The add clearly states for sit down only and not for take away, which is fine. So me and my husband went on 16 July 2024 (Tuesday), we sat down, ordered the special and had a drink. I could not finish my burger, so I asked the waiter for a packet for my leftovers and he said he is not allowed. I asked for the manager and he said the same. So I gave the arguement that I did not came in and order to take home, I merely couldnt finish my meal. Now they want me to pay but I am not allowed to take the leftover home. Their response was they would throw the leftover food to the meerkats. I feel this is very unprofessional. And dont get me wrong, the food was outstanding and the service was very nice and friendly. I just do not agree how they went about with the 'left over' situation.