barometer sensor

What is the barometer sensor? My bf went to iCare store in Thailand to change his iPhone XS Max screen (10000THB approx. 392.41USD), after changed screen for 7 days, his phone restart itself in every 2 minute. We went to the iCare store again to check if they can do something for us since it happened after changed the screen. They said it because of the barometer sensor is error and ask him to left the phone at the store. After left the phone at iCare for 4 days. Staff called us and informed that the error didn't happened because of changing phone and they unable to claim it or fix it free of charge and ask us to pay extra 21000THB (approx. 633.68USD) to change to a new one. I feel disappointed because he has using this iPhone for almost 3 years and it never caused any error but the error happened after we changed the phone screen with them.