repairs

I went to samsung pavilion because my samsung s3 mini was getting very hot they said I need a new mother board sent it in to samsung and they replaced the mother board but it still overheats I found out it was the cover but after the repairs I've found my samsung to take twice as long to charge it takes over 4 hours to charge yesterday's charge was 4hours 22 min from 15 percent to full I contacted samsung to be told it's NORMAL for it to take 3 hours plus while my phone gets charged I leave it on but I don't use it till it reaches full and I use the original charger