Android Question

My Samsung Galaxy S3 charges so slow. I went to the repair it. It was said that they finished repairing and it is ready. When my battery life is flat, it takes at least 13 hours to charge to 100%. If the battery isn't fully out, it only charges about 20% in 14 hours or more.
The time it takes to charge it longer than the time I can use it. I was once using it while it was charging and it was 34% when I opened than later there was only 33%. The battery nearly goes put when I leave it there for 24 hours without using it at all.
This problem is really frustrating because I can't use it when I need it.