Any repair or work by anyone but Apple or an Apple Authorized service center voids your warranty and Apple typically will refuse to service the device after that. Since only Apple or their authorized service partners are officially approved to work on Apple iDevices, there is no retail distribution network for OEM parts and never has been. If you are not an Apple authorized service center, the only source for any parts are stolen/black market parts, salvaged parts from used devices (a common source of parts on eBay and like sources), counterfeit parts or cheap 3rd party parts that will claim to be equivalent replacement parts but often perform poorly.
SInce you opeted for a 3rd party repair, yes, Apple will refuse further support. And no, there is no offiicial nor reliable source for parts and most certainly not for OEM or claimed to be OEM parts. Sorry, you are on your own as far as repairs go at this point. You really should have gone to Apple at the beginning of your issues for a battery replacement through their official battery replacement service program ($79 in the U.S. for any iPhone model).