As has been mentioned above the full conditions and fare rules when booking are presented to you before you confirm and pay and you agree to them. Sorry if you didn’t pick it up.

It’s similar with AA booking. Make them directly on A.com and most if not all of the fare is refunded in travel credit if you can’t travel for sometimes only a nominal amount extra. On BA most non refunable fares just include a refund of taxes and fees.

In some cases depending on the reason eg medical or bereavement BA may in their discretion wave penalties but the value of the ticket held has restrictions eg only used for original passenger etc so please check if that’s the case as it may be insurance is the better way to go.