Bad camera

My s8 camera chooses when it wants to work... my camera doesnt focus all you can see at times is a blur. I've had this problem since I got the phone and when I take it to a Samsung store they wipe my phone. The camera works for a little then it doesnt work again. I didn't have this problem with previous phones and I had exactly the same apps. I've wasted a lot of time and money trying to get it sorted out but always end up with the same outcome.