Indigo Airlines — Unprofessional behaviour of airline staff and horrible customer support

I am writing to request a refund and to express my dissatisfaction regarding the incident involving my sister, who was traveling to LGW with my 73-year-old father, a wheelchair passenger with mobility issues. Initially, I had booked tickets for both of them on April 12, 2024. However, upon receiving the confirmation, the dates were changed to May 12. This led to a situation where I had to return home from Mopa Airport, which is a two-hour drive from our residence, due to my father's medical condition. Despite contacting Indigo Airline customer service immediately, I was not provided with a satisfactory solution. In order to obtain a refund for the original booking, I was informed that I needed to make a new flight reservation within an hour. Consequently, I made a new booking on April 14, 2024. After checking in from Goa and reaching Delhi Airport, they were informed that they could not board their connecting flight to Dammam Airport because my father's passport was less than 5 months away from expiring. It is perplexing why this crucial information was not communicated to them while they were in Goa. My elderly father, who is in poor health, was left stranded and instructed to return to Goa. I have documented evidence and voice recordings of all my interactions with various individuals. If a satisfactory resolution is not provided, I will be compelled to pursue legal action. This is a concise summary of the situation, as I am limited in the number of words I can type here.