Your loss. Totally reasonable imvho. If you don't show up to the cinema, hotel, plane or train you don't get your money back, and they make you pay 100% up front, not just a deposit.
https://www.theguardian.com/food/commentisfree/2023/jul/02/restaurant-deposits-are-here-to-stay-even-if-the-cost-of-living-crisis-eases
Flavours are great, takeaway dosas really don't work as they are soggy not crisp. I order dosas when eating at a small chain in Harrow, comparable flavours, crispy, and maybe 40 percent cheaper, reflecting Harrow not Peckham and that the chain has a good flow of eat in diners. But Harrow a long way!
Certainly not a generic Indian takeaway which I find all the same.