A53 battery replaced but still draining at enormous rates and phone slowed down.

[Nalike]

I had battery backup time issue and replaced it but issue persists. My old genuine battery would last long 2 days easily with have utube usage for almost 3 years. Than faced reduced backup time and replaced with new 1 but problem is thesame. Any idea what to do? And howmuch samsung service center charge for battery replacement? 

[AZaigham]

Got it checked thorougly. Some time spam softwares keep running or some time its board gets faulty due to which battery got exausted.