I want to repalce battery of my galaxy a50 from service centre can any1 pls mention the estimated the cost?

It used to charg about 60 to 62% in an hour, when i purchased it.. .after 10 months of use, it charges about 45to 48% (when fast charging option is enabled) and 52 to 55% hourly (when it is on normal charging)....is there any problem with my chargin...