Ryanair complaint: Didn’t Let me board

So, I have an Indian Passport and Irish Residence permit.
I booked a Ticket from Kiwi (on 5th Oct 2022) which gave me the connecting flights from Cork to London STD and London STD to Romania and then further to Delhi.
I checked in Immigration website that I DO NOT NEED transit visa (PFA), if I am changing flight from the same airport having Irish Residence Permit.
They didn’t let me board in saying you cannot enter in London without Transit Visa. I tried to explain them that I do not require Visa because I have Irish Residence permit and I am not changing the airport. The argument they gave is I booked ticket from Kiwi, But the Airline was Ryanair and Even If I had booked the Ticket from Ryanair, they still couldn’t have let me in. I told to show me the ation written in the document or any official website, but they didn’t help with it, they just stuck with one sentence is they couldn’t let me in. I tried calling to Ryanair Customer and tried to call as many officials as I can, but it was 22:30 PM so no one answered my calls and I eventually missed the flight, and I lost 500 Euros and had to book a different ticket on immediate basis because I had to go because of URGENCY which cost me 1600 euros more. I do not think this is acceptable at all from the Ryanair, Immigration rules cannot variate for every Airlines. I spoke with many Indian friend who went to India through London never encountered such problems only difference is they booked from different Airlines. I strongly seek Ryanair to compensate the loss I have been through because of lack of information and poor customer service.

https:www.gov.uktopicimmigration-operational-guidanceimmigration-rules