Firstly: Mobile phones are not really designed in a way that easily enables repair work. It is unlikely that there is anything much that you can do yourself other than replacing a screen and even that is fraught with perils although not difficult once you've done a couple.
To my mind, your best bet would be to get it returned to a suitable 3rd Party, usually via the place you purchased it from. You may even be able to get it repaired under some Warranty term or other.
Secondly: The repairer is very likely to find it cheaper, and easier, to swap it out with a used model, as Smartphone Models change so swiftly that spares are rarely easily available.