Receiver not working on iPhone 11 Pro Max

Hello,

I ran out into tears when my receiver stopped working on such a costly phone. 2 Months ago suddenly it got stopped working and I was suggested to visit the nearest apple centre. I went there they charged me a huge amount 0f 33, 000 telling me that they should change the complete display to change the receiver. But, though bought a mobile for that huge amount why couldn't they replace only the receiver and unnecessarily replace the complete display which is perfectly fine? I decided not to get it repaired and started using the speaker. Five days after without doing anything, it worked itself. Again, 2 days earlier it stopped working, yesterday from 5 pm to 10 pm it worked again. From again 10 pm yesterday it stopped working. It's of irritating for me. What should I do now.?