iPhone X - Battery Replacement

My son had no trouble with his phone until after he took his iPhone X to our local Apple store to have the battery replaced - 10 days later it died - he took it back to the store and they checked another battery and that was not the fault and the noticed that the LCI’s have been triggered and claim that there is water damage. His phone has not been submersed nor has it been near water - not even rain.

They are offering him a replacement phone for £575 - is it just me or is this not outrageous that we had a perfectly working phone - apart from the battery life and since Apple Store replaced the battery which cost us £67 - it has now stopped working ??? I requested that the store send the phone to Apple and they have told me to contact Apple directly - not very good service!!

I'd be understanding if we had taken it to a generic phone repair shop, but we had taken it to a legitimate Apple store to have the peace of mind and reassurance of it being done properly.Ip