I took my iPhone into the Apple Store to replace the battery in April and after 1 week I noticed that the battery health had dropped 1percent

I took my iPhone into the Apple Store to replace the battery in April and after 1 week I noticed that the battery health had dropped 1percent. I kept an eye on it and after 4 weeks the battery health had dropped by 3percent. As the new battery I had just put in was still in warranty I took the phone back to the technician at the store at Eastgate but after doing a diagnostic they informed me there’s nothing wrong with the battery they had installed and I paid a lot of money to ensure an original battery is put in my phone. Now I have a faulty battery and the store is not willing to change it for me so I must just accept the ******* job that they did on the phone. Bad service received at iPhone Store Eastgate Mall