I had an interesting experience towards the end of COVID. I wanted to fly back from Singapore to Bangkok with another airline, but flight got cancelled and I had to buy a new one-way ticket. Couldn't get one for the same day, so went to a hotel and tried to book one for early next morning. So I booked AirAsia for around 9am the next day, paid but didn't get any e-ticket. I tried to call, send messages, everything under the sun, but nothing, didn't get anything. Operator said it can take up to 18 hrs which would be AFTER my flight. When I still didn't get it 2hrs before the flight, I decided to book a new flight with another airline which worked well.
Believe it or not, I got the e-ticket from AirAsia just shy of the 18hrs, i.e. about 6 hrs after (!!) my flight. When I tried to get the money back, the message I got was that I didn't show for the flight, which is ridiculous because I didn't have an e-ticket at the time of the flight. Regular channels led to nothing, so I tried search for any executives on LinkedIn and connected with 3-4 of them and wrote to them about this issue. Luckily, one of them actually cared and managed to get me my refund (after a few weeks).
Agree, AirAsia booking app is really bad and if you want to get a refund, good luck!